Dual ic card

ABSTRACT

A dual IC card of the present invention includes: an IC module having a contact terminal portion contacting an external machine, a connecting coil configuring a contactless terminal portion by electromagnetic coupling, and an IC chip having a contact communication function and a contactless communication function; an antenna formed along a coil wiring path that defines an inductance and having a coupling coil portion electromagnetically coupling with the connecting coil of the IC module, a main coil portion formed along a coil wiring path that defines an inductance and connected to the coupling coil portion for performing contactless communication with the external machine, and a resistance-increasing portion provided in a section that forms the coil wiring path of at least one of the coupling coil portion and the main coil portion increase electrical resistance in the section; and a plate-like card body in which the antenna is arranged.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/973,399, filed on Dec. 17, 2015, which is a Bypass Continuation ofInternational Patent Application No. PCT/JP2014/066253, filed on Jun.19, 2014, which is based upon and claims the benefit of priority ofJapanese Patent Application Nos. 2013-132654, 2013-132655, and2013-132899, all filed on Jun. 25, 2013. The entire contents of whichare hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a dual IC card, and relates to a dualIC card capable of performing contact communication and contactlesscommunication, for example.

BACKGROUND

There have been proposed dual IC cards capable of performing contactcommunication and contactless communication. For example, PTLs 1 to 3each describe a dual IC card that includes an IC module having acommunication function. The IC module is electromagnetically coupled(transformer-coupled) to an antenna provided to a card body to eliminateelectrical contact between the IC module and the antenna.

With such a dual IC card having a contact communication function and acontactless communication function, communication modes can be usedaccording to the user's applications. Thus, dual IC cards have been usedfor various applications. In such a dual IC card of recent years, an ICmodule having an antenna is joined to a card body by means of aninsulative adhesive or the like, with another antenna being embedded inthe card body. Thus, the dual IC card is ensured to be capable ofreceiving power supply and performing communication between the ICmodule and the card body by the electromagnetic coupling occurringbetween the antenna of the IC module and the antenna provided to thecard body. By configuring the dual IC card in this way, unstableelectrical connection between the IC module and the card body can beminimized. This is because, if the IC module and the card body aredirectly connected via a conductive connecting member, such as solder,the connecting member may be broken when the dual IC card is bent or theconnecting member will be deteriorated with age.

As such a dual IC card in which an IC module and the card body areelectrically connected by electromagnetic coupling, the IC cardsdescribed in PTLs 1 to 3 are known, for example.

In an IC module for a dual IC card, a terminal (contact terminalportion) for an interface that contacts an external contact machine isformed on a front surface, while a connecting coil fortransformer-coupling (electromagnetic coupling) is formed on a backsurface.

The card body includes an antenna substrate having a first surface of asheet-like resin (substrate) which is provided with a coupling coilformed of a printed coil, and an antenna coil (main coil) both of whichare ensured to be resin-sealed. The coupling coil is looped to surroundan outer side of the IC chip in the IC module, when viewed in athickness direction of the sheet-like resin.

The coupling coil of the card body is transformer-coupled with theconnecting coil, and hence power supply can be received andcommunication can be performed between the antenna coil and an externalcontactless machine, such as a reader/writer.

As the applications of the dual IC cards, contact communication is usedfor applications that need reliability and security, such as largequantities of data exchange by credit-card transactions or communicationfor account settlement procedures. In contrast, contactlesscommunication is used for applications where the communication datavolume is small and the main communication is authentication, such asgate control for allowing someone to enter or leave a room.

CITATION LIST Patent Literature

Patent Literature 1: WO 99/26195

Patent Literature 2: WO 98/15916

Patent Literature 3: WO 96/35190

SUMMARY OF THE INVENTION Technical Problem

However, the conventional dual IC cards as described above have thefollowing problem.

In the case of the dual IC cards capable of performing contactcommunication and contactless communication, contactless communicationis performed using, for example, Type-A and Type-B methods defined inISO 14443. These methods involve use of a subcarrier for datatransmission from the dual IC card to a reader/writer that serves as anexternal machine.

In this regard, in the dual IC card in which the IC module and theantenna are electromagnetically coupled, the antenna provided to thecard body is not directly connected to the IC chip, and hence the loadimposed on a resonant circuit becomes lower than in the case where theantenna is directly connected to the IC chip. In other words, a Q valueof the resonant circuit becomes high in the dual IC card as a whole.

Accordingly, if the resonance frequency in the dual IC card variesrelative to the carrier due to fabrication variations or the like, forexample, the level difference between the upper sideband and the lowersideband is increased, which may adversely affect the communicationquality.

Furthermore, the conventional dual IC cards as described above have thefollowing problem.

In the conventional dual IC cards, the antenna formed of a coupling coilportion and a main coil portion is embedded in the card body made ofplastic, and the IC module is located in a recess formed in the vicinityof the coupling coil portion in the card body.

In an area in the vicinity of the recess, the thickness of the card bodydrastically changes, and hence when an external bending force is appliedto the card body, a stress is concentrated on an outer side of thebottom of the recess. Accordingly, the dual IC card tends to be easilybroken from the recess.

Particularly in a dual IC card of the type electromagnetically coupledwith an IC module, the coupling coil is located in an area that overlapswith the recess or in an area in the vicinity of the recess. Therefore,wiring of the coupling coil is adversely affected by the stressconcentration mentioned above and easily disconnected even if the cardbody is not broken. If the coupling coil is disconnected, theelectromagnetic coupling between the IC module and the antenna isimpaired, and hence contactless communication cannot be performed.

Furthermore, in the conventional dual IC cards, the number of times theconnecting coil of the IC module is looped and the number of times asecond coupling coil of the card body is looped are adjusted to therebyachieve impedance matching and optimize power supply to the IC chip.

However, the location of the second coupling coil in the card body islimited because the location of the IC module relative to the card bodyis determined by a standard (JIS X6320-2: 2009 (ISO/IEC 7816: 2007)), orthe card body needs to be provided with an embossed area (e.g., JISX6302-1: 2005 (ISO/IEC 7811-1: 2002)) where an emboss can be formed.

The present invention has been made in view of the problems set forthabove, and has an object of providing a dual IC card realizing aconfiguration in which a resonant circuit has a lower Q value, with anIC module being electromagnetically coupled to an antenna, and ensuringstable communication quality.

The present invention has been made in view of the problems set forthabove, and has an object of providing a dual IC card that decreases orminimizes the occurrence of failure due to breakage of a coupling coilwhen an external force causes a bending stress.

The present invention has been made in view of the problems set forthabove, and has an object of providing a dual IC card increasing thedegree of freedom in arranging a coupling coil in a card body.

Solution to Problem

To solve the problems set forth above, the present invention proposesthe following aspects:

A dual IC card according to a first aspect of the present inventionincludes: an IC module including a contact terminal portion contactingan external machine, a connecting coil configuring a contactlessterminal portion by electromagnetic coupling, and an IC chip having acontact communication function and a contactless communication function;an antenna including a coupling coil portion formed along a coil wiringpath that defines an inductance and electromagnetically coupling withthe connecting coil of the IC module, a main coil portion formed along acoil wiring path that defines an inductance and connected to thecoupling coil portion to perform contactless communication with theexternal machine, and a resistance-increasing portion provided in asection that forms the coil wiring path of at least one of the couplingcoil portion and the main coil portion to increase electrical resistancein the section; and a plate-like card body in which the antenna isarranged. In the resistance-increasing portion, a resistance wiringportion is provided in the section, the resistance wiring portion havinga line length larger than a length of a direct connection hypotheticallyprovided to short-cut a first point and a second point that define thesection, having the same cross-sectional area as that of the directconnection, and being formed of the same material as that of the directconnection. The resistance wiring portion provided in the section has anelectrical resistance higher than that of the direct connection providedin the section.

The coil wiring path that defines an inductance may be a wiring pathconfigured by a coil which is looped once, or a spiral wiring pathconfigured by a spiral coil which is looped a plurality of numbers oftimes.

In the dual IC card according to the first aspect of the presentinvention, it is preferably that the electrical resistance of theresistance wiring portion in the resistance-increasing portion is higherby a factor of two or more than that of the direct connection providedin the section.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the resistance-increasing portion isconfigured by a wiring pattern including a first bent pattern thatintersects the direct connection a plurality of times.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the wiring pattern configuring theresistance-increasing portion includes second bent patterns arrangedparallel to the direct connection in a multiple manner.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the resistance-increasing portion isprovided in the main coil portion.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the card body has an embossed portionformed therein; and the resistance-increasing portion is formed in anarea that does not overlap with the embossed portion.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the card body has a rectangularcontour, in plan view, having a first long side portion and a secondlong side portion; the first long side portion is provided, in thevicinity, with an emboss-processing-enabled area that is located alongthe first long side portion; the second long side portion is provided,in the vicinity, with an emboss-processing-prohibited area that islocated along the second long side portion; and theresistance-increasing portion is formed in theemboss-processing-prohibited area.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the card body is formed into arectangular shape; and the resistance-increasing portion is formed onthe coil wiring path that is linear and extends along a long side of thecard body, in an outermost of the main coil portion.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the resistance-increasing portion isformed of an aluminum layer having a thickness of not more than 30 μm.

In the dual IC card according to the first aspect of the presentinvention, it is preferable that the resistance-increasing portion isformed of an aluminum layer having a line width of not more than 0.4 mm.

A dual IC card according to a second aspect of the present inventionincludes: an IC module including a contact terminal portion contactingan external machine, a connecting coil configuring a contactlessterminal portion by electromagnetic coupling, and an IC chip having acontact communication function and a contactless communication function;an antenna including a coupling coil portion for electromagneticallycoupling with the connecting coil of the IC module, and a main coilportion connected to the coupling coil portion to perform contactlesscommunication with the external machine; and a plate-like card body inwhich the antenna is arranged and a recess is formed for accommodationof the IC module. The coupling coil portion is located at a positionoutside the recess of the card body when viewed from an opening side ofthe recess.

In the dual IC card according to the second aspect of the presentinvention, it is preferable that the card body is formed into arectangular plate, the recess has an opening formed into a substantiallyrectangular shape having four linear portions parallel to a contour ofthe card body; and the coupling coil portion has a an innermost wiringwith a line width of not less than 1 mm at a position where theinnermost wiring intersects an extension line of one linear portionamong the four linear portions, the linear portion being formed at aposition nearest to a center of the card body in a direction of ashorter dimension of the card body and extended in a longitudinaldirection of the card body.

In the dual IC card according to the second aspect of the presentinvention, it is preferable that the innermost wiring of the couplingcoil portion includes a thick line portion having a line width of notless than 1 mm and a thin line portion having a line width of less than1 mm at positions sandwiching the extension line; and the thick lineportion and the thin line portion are connected via a line widthtransition portion that has a width gradually increasing from the linewidth of the thin line portion to the line width of the thick lineportion.

A dual IC card according to a third aspect of the present inventionincludes: an IC module including a contact terminal portion contactingan external machine, a connecting coil configuring a contactlessterminal portion by electromagnetic coupling, and an IC chip having acontact communication function and a contactless communication function;an antenna including a coupling coil for electromagnetically couplingwith the connecting coil of the IC module, and a main coil connected tothe coupling coil to perform contactless communication with an externalcontactless machine; and a plate-like card body in which a recess isformed for accommodation of the IC module. The card body has asubstrate. The coupling coil includes a first coil segment provided to afirst surface that serves as an opening side of the recess of thesubstrate, and a second coil segment provided to a second surface of thesubstrate.

In the dual IC card according to the third aspect of the presentinvention, it is more preferable that the second coil segment is formedby being looped around the IC module once when viewed in a thicknessdirection of the substrate.

In the above-described dual IC card, it is more preferable that thefirst coil segment and the second coil segment at least partiallyoverlap with each other when viewed in the thickness direction of thesubstrate; and the first coil segment and the second coil segment haverespective element wires with different line width in portions where thefirst coil segment and the second coil segment overlap with each otherin the thickness direction.

In the dual IC card according to the third aspect of the presentinvention, it is more preferable that the first coil segment and thesecond coil segment have respective element wires whose difference inline width is not less than 0.5 mm in portions where the first coilsegment and the second coil segment overlap with each other in thethickness direction.

Advantageous Effects of Invention

According to the dual IC card related to the first aspect of the presentinvention, the antenna includes the resistance-increasing portion.Accordingly, there is an advantageous effect of being able to realize aconfiguration that achieves a lower Q value in the resonant circuitwhile electromagnetically coupling the IC module to the antenna, andobtain stable communication quality.

According to the dual IC card related to the second aspect of thepresent invention, the coupling coil portion is arranged at the positionoutside the recess. Accordingly, there is an advantageous effect ofbeing able to decrease or even minimize failure due to a disconnectionin the coupling coil in the event that a bending stress due to anexternal force is generated.

According to the dual IC card related to the third aspect of the presentinvention, the degree of freedom in arranging the coupling coil in thecard body can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view illustrating a dual IC card according toa first embodiment of the present invention.

FIG. 2 is a cross section taken along a line A-A of FIG. 1.

FIG. 3 is a schematic plan view illustrating an arrangement of anantenna of the dual IC card according to the first embodiment of thepresent invention.

FIG. 4 is a schematic enlarged view illustrating a coupling coil portionprovided in the vicinity of a recess of the dual IC card according tothe first embodiment of the present invention.

FIG. 5A is a partially enlarged plan view that shows illustrating aresistance-increasing portion, and a schematic diagram illustrating awiring pattern, in the dual IC card according to the first embodiment ofthe present invention.

FIG. 5B is a partially enlarged plan view that shows illustrating aresistance-increasing portion, and a schematic diagram illustrating awiring pattern, in the dual IC card according to the first embodiment ofthe present invention.

FIG. 6 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to a firstmodification of the first embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to a secondmodification of the first embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to a thirdmodification of the first embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to a fourthmodification of the first embodiment of the present invention.

FIG. 10 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to a fifthmodification of the first embodiment of the present invention.

FIG. 11A is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to sixth andseventh modifications of the first embodiment of the present invention.

FIG. 11B is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the sixthand seventh modifications of the first embodiment of the presentinvention.

FIG. 12 is a schematic plan view illustrating a dual IC card accordingto a second embodiment of the present invention.

FIG. 13 is a schematic plan view illustrating an arrangement of anantenna of the dual IC card according to the second embodiment of thepresent invention.

FIG. 14A is a schematic diagram illustrating a state where the dual ICcard according to the second embodiment of the present invention hasbeen bent and deformed.

FIG. 14B is a schematic diagram illustrating a state where the dual ICcard according to the second embodiment of the present invention hasbeen bent and deformed.

FIG. 15 is a schematic cross section illustrating a side surface of adual IC card according to a third embodiment of the present invention.

FIG. 16 is a partially transparent plan view illustrating a card body ofthe dual IC card according to the third embodiment of the presentinvention is made transparent.

FIG. 17 is an enlarged view of a part A of FIG. 15.

FIG. 18 is an equivalent circuit diagram illustrating a principle of thedual IC card according to the third embodiment of the present invention.

FIG. 19 is a cross section illustrating a major part of a dual IC cardaccording to a modification of the third embodiment of the presentinvention.

FIG. 20 is a cross section of a major part of the dual IC card accordingto a modification of the third embodiment of the present invention.

DESCRIPTION OF REPRESENTATIVE EMBODIMENTS First Embodiment

With reference to the drawings, a first embodiment of a dual IC cardaccording to the present invention will be described.

FIG. 1 is a schematic plan view illustrating the dual IC card accordingto the first embodiment of the present invention. FIG. 2 is a crosssection taken along a line A-A of FIG. 1. FIG. 3 is a schematic planview illustrating an arrangement of an antenna of the dual IC cardaccording to the first embodiment of the present invention. FIG. 4 is aschematic enlarged view illustrating a coupling coil portion provided inthe vicinity of a recess of the dual IC card according to the firstembodiment of the present invention. FIG. 5A is a partially enlargedplan view illustrating a resistance-increasing portion in the dual ICcard according to the first embodiment of the present invention. FIG. 5Bis a schematic diagram illustrating a wiring pattern of FIG. 5A.

As shown in FIGS. 1 to 3, a dual IC card 1 according to the firstembodiment is a device capable of performing contact communication andcontactless communication between the dual IC card 1 and an externalmachine. The dual IC card 1 includes a card body 2 having asubstantially rectangular outline in plan view, as well as an IC module3 and an antenna 4 provided to the card body 2.

The shape or an outline that can be used for the dual IC card 1 may beone that conforms, as appropriate, to card standards.

The card body 2 is formed into a plate-like shape with a width Lx alonga long side (see FIG. 1), a width Ly along a short side (see FIG. 1,Ly<Lx), and a thickness t (see FIG. 2), and has a substantiallyrectangular contour, with the four corners being rounded in plan view.For example, if the dual IC card 1 conforms to JIS X6301: 2005 (ISO/IEC7816: 2003), the nominal values of Lx, Ly and t are Lx=85.60 (mm),Ly=53.98 (mm), t=0.76 (mm), while a corner R is R=3.18 (mm).

Materials that can be used for the card body 2 include resin materialsthat can provide appropriate electrically insulating properties anddurability. As examples of favorable materials, mention can be made, forexample, of vinyl chloride-based materials, such as polyvinyl chloride(PVC), polycarbonate-based materials, polyethylene terephthalatecopolymers (PET-G), and the like.

A configuration that can be used for the card body 2 includes aconfiguration in which two or more card bases made of the abovematerials are laminated with each other.

The card body 2 has a front surface 2 e on which characters or the like,not shown, are described or emboss-molded in a relief-like manner. Onthe surface 2 e, these characters or the like expressing information arearrayed in a correct orientation in a state where long sides arehorizontally located as shown in FIG. 1.

When the card body 2 is located as mentioned above, a side surface thatconfigures the upper long side is hereinafter referred to as a firstlong side portion 2 a, a side surface that configures the lower longside as a second long side portion 2 b, a side surface that configures aleft short side as a first short side portion 2 c, and a side surfacethat configures a right short side as a second short side portion 2 d.

For convenience of referring to directions, a direction along the longsides may be referred to as an x direction and a direction along theshort sides may be referred to as a y direction.

Hereinafter, the IC module 3 arranged in the card body 2 will bedescribed.

As shown in FIG. 2, the IC module 3 has a connecting terminal portion 31(a contact terminal portion) brought into contact with an externalmachine for electrical connection therewith, a connecting coil 34 thatconfigures a contactless terminal portion that causes electromagneticcoupling, and an IC chip 33 having a contact communication function anda contactless communication function.

The connecting terminal portion 31 is configured with a plurality ofelectrodes formed on one surface of a module substrate 32. Theelectrodes are exposed to the outside of the card body 2 while beingaligned to the front surface 2 e of the card body 2. As long as theterminal position of the connecting terminal portion 31 satisfies theterminal position defined in the ISO/JIS standard, the contour anddimension of each of the contact terminal portion 31 and the modulesubstrate 32 are not particularly limited.

The contour of the connecting terminal portion 31, in plan view, isensured to coincide with the contour of the module substrate 32. Asshown in FIG. 1, the connecting terminal portion 31 has a rectangularshape with its four corners being rounded.

Linear portions of the contours of the connecting terminal portion 31and the module substrate 32 are extended along the x or y direction.

The shape or arrangement of each electrode of the connecting terminalportion 31 is set based on the standard to which the dual IC card 1conforms. In the first embodiment, the connecting terminal portion 31 ispositioned in the vicinity of the first short side portion 2 c in termsof the x direction, while being positioned somewhat closer to the firstlong side portion 2 a than to a widthwise center in terms of the ydirection.

For example, the shape shown as an example in FIG. 1 corresponds to aterminal arrangement defined in JIS X6320-2: 2009 (ISO/IEC 7816: 2007).

Specifically, according to the definition of the standard, a firstterminal portion 3 a, a second terminal portion 3 b, and a thirdterminal portion 3 c are arrayed along the y direction, for contact withthe “C1 terminal”, the “C2 terminal”, and the “C3 terminal”,respectively. Furthermore, according to the definition of the standard,a fourth terminal portion 3 d, a fifth terminal portion 3 e, and a sixthterminal portion 3 f are arrayed at positions facing these respectiveterminals in the x direction, for contact with the “C5 terminal”, the“C6 terminal”, and the “C7 terminal”, respectively. In FIG. 1, theposition of the “C1 terminal” or the like is indicated by a two-dotchain line on the first terminal portion 3 a or the like, with a sign C1or the like being assigned.

The first, second, third, fourth, fifth, and sixth terminal portions 3a, 3 b, 3 c, 3 d, 3 e, and 3 f are electrically connected to the IC chip33 via wiring, not shown.

To realize such an electrode arrangement, the contour of the connectingterminal portion 31 in the first embodiment has an x-direction width of13.0 mm and a y-direction width of 11.8 mm.

Further, in the contour of the connecting terminal portion 31, a sidenearest to the first short side portion 2 c of the card body 2 among theplurality of sides forming the contour is located at a position spacedapart from the first short side portion 2 c by 9.0 mm in the xdirection. A side nearest to the second long side portion 2 b of thecard body 2 among the plurality of sides forming the contour of theconnecting terminal portion 31 is located at a position spaced apartfrom the second long side portion 2 b by 26.0 mm in the x direction.

As shown in FIGS. 1 and 2, the connecting coil 34 is arranged beingformed into a spiral shape and being looped around the IC chip 33 on themodule substrate 32 along the contour of the connecting terminal portion31, the arrangement being on an opposite side of the connecting terminalportion 31. The connecting coil 34 is electrically connected to the ICchip 33.

The IC chip 33 is arranged on the module substrate 32 so as to belocated inner side of the connecting coil 34, the arrangement being onthe opposite side of the connecting terminal portion 31. The IC chip 33is electrically connected to the connecting terminal portion 31 and theconnecting coil 34 via wiring, not shown.

To fabricate such an IC module 3, the module substrate 32 is preparedfirst, which is configured by a glass epoxy substrate or an insulatingsubstrate, such as a PET sheet, having a thickness of 50 μm to 200 μm,for example. Afterwards, a copper foil pattern or the like formed byetching or the like is provided, for example, to the front and backsurfaces of the module substrate 32 to thereby form a wiring patternthat includes the connecting terminal portion 31 and the connecting coil34. At this time, if the wirings formed on the front and back surfacesof the module substrate 32 need to be connected, a through hole or thelike, for example, is formed in the module substrate 32 to electricallyconnect these wirings with each other.

Exposed portions of the copper foil pattern formed on each of the frontand back surfaces are furnished with a nickel plating of thickness 0.5μm to 3 μm, for example, and further, the nickel plating layer isfurnished with a gold plating of thickness 0.01 μm to 0.3 μm.

The IC chip 33 is bonded to the back surface of the module substrate 32by means of a die-attach adhesive, for example. For example, the IC chip33 is connected to the connecting terminal portion 31, the connectingcoil 34, or a wiring pattern connected to them, by performing wirebonding using a wire of gold, copper, or the like, having a diameter of10 μm to 40 μm. The IC chip 33 is sealed by a resin seal 36 made such asof an epoxy resin, for example.

Such a fabrication method is only an example. For example, using anothermethod, the connecting terminal portion 31 may be formed of a lead framehaving a thickness of 50 μm to 200 μm, and the connecting coil 34 may beformed on a back surface of the lead frame using a copper wire.

As shown in FIGS. 2 and 3, to accommodate the IC module 3 having such aconfiguration, the card body 2 is formed with an IC module accommodatingportion 21 that is a recess opening in the front surface 2 e.

The IC module accommodating portion 21 includes an substantiallyrectangular first hole portion 22 and an substantially rectangularsecond hole portion 23. The first hole portion 22 has an opening intowhich the connecting terminal portion 31 and the module substrate 32 arefitted, the opening being larger than the contour of the modulesubstrate 32. The second hole portion 23 accommodates the resin seal 36which protrudes from the module substrate 32 by a length larger than thelength by which the connecting coil 34 protrudes from the modulesubstrate 32. The second hole portion 23 is provided to a bottom of thefirst hole portion 22.

As indicated in FIGS. 3 and 4 by the two-dot chain line, a linearportion of the opening of the first hole portion 22 in plan view is madeup of a first side surface portion 22 a parallel to and nearest to thefirst long side portion 2 a among a plurality of sides configuring thefirst hole portion 22, a second side surface portion 22 b parallel toand nearest to the second long side portion 2 b among the plurality ofsides configuring the first hole portion 22, a third side surfaceportion 22 c parallel to and nearest to the first short side portion 2 camong the plurality of sides configuring the first hole portion 22, anda fourth side surface portion 22 d parallel to and nearest to the secondshort side portion 2 d among the plurality of sides configuring thefirst hole portion 22.

The first side surface portion 22 a is formed at a position apart fromthe first long side portion 2 a by 16.6 mm.

The second side surface portion 22 b is formed at a position apart fromthe second long side portion 2 b by 25.4 mm, and is positioned atsubstantially the widthwise center of the card body 2 in the ydirection.

The third side surface portion 22 c is formed at a position apart fromthe first short side portion 2 c by 8.4 mm.

The fourth side surface portion 22 d is formed at a position apart fromthe second short side portion 2 d by 64.0 mm, and is formed at aposition closer to the first short side portion 2 c than to thewidthwise center of the card body 2 in the x direction.

In the opening of the IC module accommodating portion 21 formed in thisway, the second side surface portion 22 b is formed at a positionnearest to the center of the card body 2 in the short side direction ofthe card body 2, among the four linear portions, namely, the first,second, third, and fourth side surface portions 22 a, 22 b, 22 c, and 22d. The second side surface portion 22 b is a linear portion that extendsin a longitudinal direction of the card body 2.

As shown in FIG. 2, the depth of the first hole portion 22 is set to belarger than the sum of the thicknesses of the connecting terminalportion 31, the module substrate 32, and the connecting coil 34.Accordingly, the depth of the first hole portion 22 is determined suchthat a gap is formed between the bottom of the first hole portion 22 andthe connecting coil 34, with the front surface of the connectingterminal portion 31 being aligned to the front surface 2 e.

The depth of the second hole portion 23 is determined such that a gap isformed between the bottom of the second hole portion 23 and the resinseal 36, with the front surface of the connecting terminal portion 31being aligned to the front surface 2 e.

The IC module 3 is fitted to, and fixed by bonding to, the IC moduleaccommodating portion 21 having the above configuration, such that thefront surface of the connecting terminal portion 31 falls within a rangedefined in JIS X6320-1: 2009 (ISO 7816-1: 1998, Amd1: 2003) relative tothe front surface 2 e.

Accordingly, as shown in FIG. 2, an adhesive layer 35 made of asolidified adhesive is formed between the bottom of each of the firstand second hole portions 22 and 23, and the module substrate 32.However, there can also be adopted a configuration in which no adhesivelayer 35 is arranged at the bottom of the second hole portion 23.

Character information can be appropriately provided by emboss-molding ina specific area of the card body 2. In the first embodiment,emboss-molding can be performed in a first embossed area 5 (anemboss-processing-enabled area) and a second embossed area 6 (anemboss-processing-enabled area) shown in FIG. 1.

For example, when conforming to JIS X6302-1: 2005 (ISO/IEC 7811-1:2002), the first embossed area 5 serves as an “identification numberarea” where one row of character strings can be provided byemboss-molding. The second embossed area 6 serves as a “name and addressarea” where one row of character strings can be provided byemboss-molding.

The range of the first and second embossed areas 5 and 6 corresponds toa stripe-like area that extends in the longitudinal direction of thecard body 2. The first and second embossed areas 5 and 6 are arranged inthis order in a direction from the first long side portion 2 a towardthe second long side portion 2 b in they direction. A specific layoutposition of each of the first and second embossed areas 5 and 6 isdefined in the above standard.

For example, a boundary 5 a of the first embossed area 5 on the firstlong side portion 2 a side (boundary portion of the first embossed area5, the portion being closer to the first long side portion 2 a than tothe second long side portion 2 b) is positioned being spaced apart fromthe second long side portion 2 b by a maximum of 24.03 mm, so as to bepositioned slightly closer to the second long side portion 2 b than tothe widthwise center in the y direction.

The x-direction range of each of the first and second embossed areas 5and 6 (the width range) corresponds to a range obtained by removingareas of approximately a few millimeters positioned in the vicinity ofthe first and second short side portions 2 c and 2 d (areas ranging fromboth ends in inward directions), from the x-direction width range of thedual IC card 1.

A configuration of the antenna 4 will now be described.

The antenna 4 is electromagnetically coupled to the IC chip 33 via theconnecting coil 34 of the IC module 3 to enable electric power supply tothe IC chip 33 from outside and enables contactless communicationbetween the IC chip 33 and an external machine, not shown. As shown inFIG. 3, the antenna 4 is formed on a front surface of a sheet substrate41 formed of an insulator in a rectangular shape in plan view which issmaller than the contour of the card body 2, and embedded insubstantially the center portion in the thickness direction of the cardbody 2.

The antenna 4 in the thickness direction is laid out at a positiondeeper than the position of the bottom surface of the first hole portion22 but shallower than the position of the bottom surface of the secondhole portion 23, in the IC module accommodating portion 21. Accordingly,a substantially rectangular hole that is in the same shape as that ofthe second hole portion 23 is formed through the sheet substrate 41.

A schematic configuration of the antenna 4 includes a coupling coilportion 4A and a main coil portion 4B, each of which is formed of awiring arranged on the sheet substrate 41, and a capacitive element 42connected between an end of the coupling coil portion 4A and an end ofthe main coil portion 4B.

The coupling coil portion 4A is arranged in the vicinity of theconnecting coil 34 of the IC module 3, for electromagnetic coupling withthe connecting coil 34 of the IC module 3. The coupling coil portion 4Ais configured by a wiring that is looped around the connecting coil 34one to ten times (i.e., 1 to 10 times looping) in an outer area of thecoil.

In the first embodiment, the coupling coil portion 4A is configured by awiring which is looped around the connecting coil 34 five times in theouter area of the coil. The wiring of the coupling coil portion 4A isformed by patterning a metal layer having a thickness T by etching orthe like.

As shown in FIG. 4, a substantially circular land portion R1 forestablishing electrical continuity with the capacitive element 42 isformed at an innermost end of the coupling coil portion 4A.

The land portion R1 according to the first embodiment is formed at aposition that intersects the fourth side surface portion 22 d of thefirst hole portion 22 so as to be located in a portion on the sheetsubstrate 41.

The land portion R1 is electrically connected to a substantiallycircular land portion R2 which is formed by crimping on the back surfaceof the sheet substrate 41. The land portions R1 and R2 may beelectrically connected to each other by means of an electricallyconductive paste, resistance welding, laser welding, or the like.

A coil wiring A1 configuring innermost first looping of the couplingcoil portion 4A is made up of a thin line portion A1 d having a linewidth W and routed from the land portion R1 along the fourth sidesurface portion 22 d, a thin line portion Ala having a line width W androuted along the first side surface portion 22 a, a thin line portion A1c having a line width W and routed along the third side surface portion22 c, and a thick line portion A1 b having a line width W1 b and routedalong the second side surface portion 22 b. The line width can have arelationship expressed by W1 b>W.

A coil wiring A2 that configures second looping of the coupling coilportion 4A is routed along the outer side of the coil wiring A1, from anend of the thick line portion A1 b of the coil wiring A1, the end beingclose to the second short side portion 2 d, including the land portionR1. The coil wiring A2 has thin line portions A2 d, A2 a, and A2 c eachhaving a line width W, and a thick line portion A2 b having a line widthW2 b. The thin line portions A2 d, A2 a, and A2 c are routed along theland portion R1 and the thin line portions A1 d, A1 a, and A1 c. Thethick line portion A2 b is routed along the thick line portion A1 b. Theline width can have a relationship expressed by W2 b>W1 b.

Similarly, as shown in FIG. 3, a coil wiring A3 as third looping isrouted from an end of the thick line portion A2 b close to the secondshort side portion 2 d. A coil wiring A4 as fourth looping is routedfrom an end of the coil wiring A3. A coil wiring A5 as fifth looping isrouted from an end of the coil wiring A4.

The respective wiring configurations of the coil wirings A3, A4, and A5are as follows. Specifically, the coil wiring A3 is formed of thin lineportions A3 d, A3 a, and A3 c (see FIG. 4) and an L-shaped thick lineportion A3 b (see FIG. 3). The coil wiring A4 is formed of thin lineportions A4 d, A4 a, and A4 c (see FIG. 4) and an L-shaped thick lineportion A4 b (see FIG. 3). The coil wiring A5 is formed of thin lineportions A5 d, A5 a, and A5 c (see FIG. 4) and a thick line portion A5 b(see FIG. 3).

Each thin line portion in the coil wirings A3, A4, and A5 has a linewidth W.

All of the thick line portions A3 b, A4 b, and A5 b have a common linewidth W3 b. The line widths can have a relationship expressed by W1 b<W3b<W2 b.

The thick line portion A3 b is routed parallel to the thick line portionA2 b extending in the x direction, bent at the end of the thick lineportion A2 b near the second short side portion 2 d, and extended alongthe y direction of the thick line portion A2 b.

The thick line portion A4 b is disposed parallel to the thick lineportion A3 b extending in the x direction, bent at the end of the thickline portion A3 b near the second short side portion 2 d, and extendedalong the y direction of the thick line portion A3 b.

Each thin line portion favorably has a line width W of not less than 0.1mm and less than 1 mm. As an example, the line width W is 0.4 mm in thefirst embodiment.

The thick line portion A1 b has a line width W1 b which is set to be notless than 1 mm but not to allow the thick line portion A1 b to overlapwith the first embossed area 5. Thus, the thick line portion A1 b isextended along the boundary 5 a of the first embossed area 5, whilebeing positioned outside the range of the first embossed area 5 (seeFIG. 1).

As shown in FIG. 1, in the first embodiment, the thick line portion A2 bis formed at a position that overlaps with the first embossed area 5.The line width W2 b of the thick line portion A2 b is substantially thesame (or the same) as the width of the first embossed area 5 in the ydirection, and is made larger than the y-direction width of thecharacters formed in the first embossed area 5. This eliminates the riskof breaking the thick line portion A2 b when an embossed portion isformed in the first embossed area 5.

The line width W3 b of each of the thick line portions A3 b, A4 b, andA5 b is made larger than the y-direction width of the characters in eachrow formed in the second embossed area 6. This eliminates the risk ofbreaking the thick line portions A3 b, A4 b, and A5 b when an embossedpart is formed in the second embossed area 6.

As shown in FIG. 4, a line width transition portion Atc is providedbetween an end of the thick line portion A1 b and an end of the thinline portion A1 c to allow a line width to gradually change from W to W1b. Similarly, a line width transition portion Atd is provided between anend of the thick line portion A1 b and an end of the thin line portionA2 d to allow a line width to gradually change from W1 b to W.

The shapes of the line width transition portions Atc and Atd are setsuch that line widths We and Wd along an extension line Lb of the secondside surface portion 22 b are equal to or more than 1 mm, respectively,so as to improve durability against bending.

In the first embodiment, the line width transition portion Atc has aline width that gradually increases from the end of the thin lineportion A1 c outwardly from the first hole portion 22. At the cornerportion along a rounded corner of the first hole portion 22, the linewidth of the line width transition portion Atc has a maximum value Wr(the line width can be Wr≥W1 b). In this way, the line width transitionportion Atc is provided to have a shape for smoothly establishingconnection with the straight portion of the thick line portion A1 bhaving the line width W1 b. As a specific example, the dimension can beW=0.4 (mm), Wr=1.6 (mm), W1 b=0.5 (mm), and Wc=2.6 (mm).

The thick line portion A1 b connected to the line width transitionportion Atd is bent along the rounded corner of the first hole portion22 while maintaining the line width W1 b. As the thick line portion A1 bextends in a diagonal direction along the land portion R1, the linewidth of the thick line portion A1 b gradually decreases to the linewidth W. The line portion that has reduced the line width in this way isprovided to have a shape for smoothly establishing connection with theend of the thin line portion A2 d that is arcuately routed along theouter side of the land portion R1 close to the second short side portion2 d. As specific example, the dimension according to such a shape can beWd=2.6 (mm).

With this configuration, the inductance of the coupling coil portion 4Ais calculated as the inductance of a coil that has a spiral (volute)wiring pattern made by concatenating the center lines of the line widthsof the coil wirings A1, A2, A3, A4, and A5. Accordingly, the path madeby concatenating the center lines of the line widths of the coil wiringsA1, A2, A3, A4, and A5 coincides with a coil wiring path that definesthe inductance of the coupling coil portion 4A.

As described above, the coupling coil portion 4A is arranged outside theIC module accommodating portion 21. The reason for this is to preventthe wiring from being located immediately below a corner portion wherestress concentration occurs when an external force acts on the dual ICcard 1 to bend the card. For example, the corner portion corresponds toa portion where the first, second, third, or fourth side surface portion22 a, 22 b, 22 c or 22 d intersects the bottom surface of the first holeportion 22 (see the two-dot chain line of FIG. 4).

The coil wiring A1 that extends along the second side surface portion 22b is the thick line portion A1 b having a line width of not less than 1mm. The reason for this is to improve durability of the coil wiring A1against the stress concentrated on a corner portion formed by the secondside surface portion 22 b. Such a stress is caused in the case where theantenna 4 or the IC module accommodating portion 21 is displaced byfabrication variations to allow the coil wiring A1 to overlap with thecorner portion in question, followed by bending along the y direction.

The line width transition portions Atc and Atd are provided in portionsoverlapping and intersecting the extension line Lb of the second sidesurface portion 22 b, and the line widths We and Wd overlapping with theextension line Lb are rendered to be not less than 1 mm. The reason forthis is to prevent breakage of the coil wiring A1 caused by a highstress field on the extension line of the corner portion formed by thesecond side surface portion 22 b.

As shown in FIG. 3, the main coil portion 4B in the first embodimentforms a coil opening in an area adjacent to the IC module 3, so as toperform reception/transmission in contactless communication with anexternal machine and receive power supply from the external machine. Themain coil portion 4B is connected to an end of the thick line portion A5b of the coupling coil portion 4A, the end being close to the secondshort side portion 2 d. In the first embodiment, the main coil portion4B, as a whole, is configured by a wiring looped three times and havingdifferent line widths depending on the location of the wiring. Similarto the main coil portion 4B, the wiring of the main coil portion 4B isformed by patterning a metal layer having a thickness T by etching orthe like.

The main coil portion 4B has an outermost wiring that is a coil wiringB3 configuring third looping. The coil wiring B3 is formed of a thickline portion B3 b having a line width W3 b and routed in the x directionat a position contiguous with the second long side portion 2 b, a thickline portion B3 d having a line width W3 d and routed in the y directionat a position contiguous with the second short side portion 2 d (W<W3d<W3 b), a resistance-increasing portion B3 a routed in the x directionat a position contiguous with the first long side portion 2 a, and athick line portion B3 c routed in the y direction at a positioncontiguous with the coupling coil portion 4A.

The line width of the thick line portion B3 c located close to the firstlong side portion 2 a is W3 d which is equal to the line width of thethick line portion B3 d. The thick line portion B3 c has a portionparallel to the thick line portion A4 b of the coupling coil portion 4Aand having a line width which is increased so as to be equal to W3 b ofthe thick line portion A4 b.

The resistance-increasing portion B3 a, the shape of which is shown indetail in FIG. 5A, is a wiring portion (resistance wiring portion) thathas a rectangular wave-like wiring pattern formed in a range of ±habetween a point P1 (first point) and a point P2 (second point) (section)along a straight line O (direct connection, see the imaginary line)extending in the x direction.

The resistance-increasing portion B3 a has a line width of a constantvalue Wa (Wa≤W). FIG. 5B shows a wiring pattern made by concatenatingthe center line of the line width. As shown in FIG. 5B, a wavelengthalong the straight line O is da. Accordingly, the wiring pattern of theresistance-increasing portion B3 a has amplitude expressed by ha−Wa/2.

The line width Wa is set to an appropriate value equal to or more than alower limit value of the line width which is suitable for stablyfabricating an etched antenna by means of a gravure plate resistprinting method used for generally used dual IC cards. Also, thissetting of the line width Wa is necessary for imparting durability tothe dual IC card 1 when an external force is applied to the card.

In the electromagnetic coupling-type dual IC card, the line width Wa ispreferably small so as to increase the electrical resistance anddecrease the Q value in a limited antenna shape. For example, the linewidth W of each thin line portion is preferably not less than 0.1 mm butnot more than 1 mm, and a dimension of about 0.4 mm is particularlypreferable.

In contrast, the line width in the resistance-increasing portion B3 a ispreferably equal to or less than the line width W of each thin lineportion, and the line width of not more than 0.4 mm is particularlypreferable. More preferably, the line width in the resistance-increasingportion B3 a is less than the line width W of each thin line portion,and particularly less than 0.4 mm.

According to the resistance-increasing portion B3 a that has such awiring pattern, the wiring path of the resistance wiring portion isprovided to extend along a rectangular wave that generates oscillationcentering on the straight line O (direct connection), in the sectionbetween the point P1 (first point) and the point P2 (second point).Accordingly, the pattern of the wiring configuring theresistance-increasing portion B3 a has a first bent pattern thatintersects the direct connection a plurality of times.

Accordingly, in wiring portions extending in the y direction, currentsare passed in different directions in the mutually adjacent wiringportions, causing mutual cancellation of magnetic fields. Accordingly,the mutually adjacent wiring portions do not contribute to theinductance.

In wiring portions extending in the x direction, wiring portions L1 at alocation of decreasing an opening area of the coil wiring B3 arealternated with wiring portions L2 at a location of increasing theopening area of the coil wiring B3. The sum of a decrease S2 and anincrease S1 of an opening area is ensured to be zero.

Consequently, the opening area that defines the inductance of the coilwiring B3 is determined by the coil wiring path made by concatenatingthe center lines of the line widths of the thick line portions B3 b andB3 d, the straight line O, and the center lines of the line widths ofthe thick line portion B3 c. Accordingly, the inductance caused by thecoil wiring B3 is equivalent to the inductance of a coil wiringcalculated when a linear wiring along the straight line O is arranged inplace of the resistance-increasing portion B3 a.

In contrast, a line length LB3 a, which is a length measured along thecenter of the line width in the resistance-increasing portion B3 a, isexpressed by the following Expression (1) when a length of theresistance-increasing portion B3 a along the straight line O (lengthbetween the points P1 and P2) is taken as L_(O) and the number ofrectangular waves is taken as N:

L _(B3a) L _(O)4·N·(ha−Wa/2)  (1)

Let us discuss herein a coil wiring that has an inductance equal to thatof the resistance-increasing portion B3 a of the coil wiring B3(hereinafter referred to as an equivalent coil wiring B3′). Theequivalent coil wiring B3′ having the same cross-sectional area as thatof the wiring of the resistance-increasing portion B3 a is formed of thesame material as that of the resistance-increasing portion B3 a and hasa length L_(O). In this case, the electrical resistance of the coilwiring B3 increases proportionately with the increase of the line lengthof the resistance-increasing portion B3 a (L_(B3a)−L_(O)), compared tothe electrical resistance of the equivalent coil wiring B3′.

In other words, by allowing the coil wiring B3 to have theresistance-increasing portion B3 a, the electrical resistance of thecoil wiring B3 is increased without changing the inductance of theequivalent coil wiring B3′. Accordingly, the resistance-increasingportion B3 a is provided, between the points P1 and P2, with aresistance wiring portion having a line length larger than that of thedirect connection (straight line O) that hypothetically link the pointsP1 and P2 defining the section, having the same cross-sectional area asthat of the direct connection, and formed of the same material as thatof the direct connection. The electrical resistance of the resistancewiring portion provided in this section is higher than the electricalresistance in the case where the direct connection is provided in thissection.

The electrical resistance of the resistance-increasing portion B3 a isset to a value necessary for obtaining a preferable value in theelectrical resistance of the resonant circuit caused by the antenna 4.Particularly, the electrical resistance of the resistance-increasingportion B3 a is preferably set such that the Q value of the antenna 4becomes a proper value.

The electrical resistance of the resistance-increasing portion B3 a ispreferably set to be higher by a factor of two or more than theelectrical resistance of the wiring (direct connection) positionedbetween both ends of the resistance-increasing portion B3 a to extendalong the coil wiring path, having the same cross-sectional area as thatof the wiring of the resistance-increasing portion B3 a, and formed ofthe same material as that of the resistance-increasing portion B3 a. Inthe first embodiment, the electrical resistance of theresistance-increasing portion B3 a is preferably set to be higher by afactor of two or more than the electrical resistance of the linearwiring formed of the material mentioned above and having thecross-sectional area and length L_(O) mentioned above.

In other words, the electrical resistance of the resistance wiringportion of the resistance-increasing portion B3 a is preferably higherby a factor of two or more than the electrical resistance in the casewhere the direct connection is provided in the section between thepoints P1 and P2.

The main coil portion 4B has a coil wiring B2 that configures secondlooping. The coil wiring B2 is routed along the inner side of the coilwiring B3 from the end of the thick line portion B3 c, the end beingclose to the second long side portion 2 b. The coil wiring B2 is formedof a thick line portion B2 b having a line width W3 b and extendingalong the thick line portion B3 b, a lateral wiring portion B2 dextending along the thick line portion B3 d, a thin line portion B2 ahaving a line width W and extending along the resistance-increasingportion B3 a, and a lateral wiring portion B2 c extending along thethick line portion B3 c.

The lateral wiring portions B2 d and B2 c parallel to the thick lineportion A4 b of the coupling coil portion 4A and close to the secondlong side portion 2 b include portions each having a line width W3 b.The lateral wiring portions B2 d and B2 c close to the first long sideportion 2 a include portions each having a line width W. The portionshaving different line widths in this way are mutually linked via anintermediate wiring portion that has a wiring width of not less than theline width W.

In the first embodiment, these intermediate wiring portions are formedat positions closer to the first long side portion 2 a than to theextension line Lb of the second side surface portion 22 b. Accordingly,the intermediate wiring portions can both have the line width W3 b onthe extension line Lb.

The main coil portion 4B has a coil wiring B1 that configures firstlooping. The coil wiring B1 is routed along the inner side of the coilwiring B2 from the end of the lateral wiring portion B2 c, the end beingclose to the second long side portion 2 b. The coil wiring B1 is formedof a thick line portion B1 b having a line width W3 b and extendingalong the thick line portion B2 b, a lateral wiring portion B1 dextending along the lateral wiring portion B2 d, a thin line portion B1a having a line width W and extending along the thin line portion B2 a,and a thin line portion B1 c having a width W and extending along thelateral wiring portion B2 c.

The lateral wiring portion B1 d parallel to the thick line portion A4 bof the coupling coil portion 4A and close to the second long sideportion 2 b includes a portion having a line width W3 b. The lateralwiring portion B1 d close to the first long side portion 2 a includes aportion having a line width W.

The portions having different line widths in this way are mutuallylinked via an intermediate wiring portion that has a wiring width of notless than the line width W.

In the first embodiment, the intermediate wiring portions are formed atpositions closer to the first long side portion 2 a than to theextension line Lb of the second side surface portion 22 b. Accordingly,the intermediate wiring portions can both have a line width W3 b on theextension line Lb.

The thin line portion B1 c extends halfway of the lateral wiring portionB2 c having a line width W and terminates. This termination portion iselectrically connected to the capacitive element 42 via a wiring Ta.

With this configuration, the inductance of the main coil portion 4B iscalculated as the inductance of a coil having a spiral wiring patterncorresponding to the concatenation of the center lines of the linewidths of the coil wirings B1 and B2 and the equivalent coil wiring B3′.Accordingly, the path that is the concatenation of the center lines ofthe line widths of the coil wirings B1 and B2 and the equivalent coilwiring B3′ configures a coil wiring path that defines the inductance ofthe main coil portion 4B.

The capacitive element 42 is a circuit element forming a capacitancethat determines the resonance frequency of the antenna 4 to performcontactless communication. The capacitive element 42 according to thefirst embodiment is configured by a first electrode 42 a in arectangular shape and provided to the front surface of the sheetsubstrate 41 where the coupling coil portion 4A and the main coilportion 4B are formed, and a second electrode 42 b in a rectangularshape and provided on the back surface side of the sheet substrate 41 soas to be located at a position opposed to the first electrode 42 a.

The first electrode 42 a is electrically connected to the innermost endof the main coil portion 4B via the wiring Ta.

The second electrode 42 b is electrically connected to the land portionR2 via a wiring Tb.

As mentioned above, since the land portion R2 is electrically continuousto the land portion R1, the second electrode 42 b is electricallyconnected to the innermost end of the coupling coil portion 4A.

With this configuration, the antenna 4 configures a closed circuit inwhich the coupling coil portion 4A, the main coil portion 4B, and thecapacitive element 42 are serially connected.

To fabricate the antenna 4 having such a configuration, the sheetsubstrate 41 made of an insulative sheet of polyethylene terephthalate(PET), polyethylene naphthalate (PEN), or the like, for example, isprepared first. Then, a metal layer, such as a copper or aluminum foil,for example, is formed on the front and back surfaces of the sheetsubstrate 41 by laminating processing or the like, for example. Then,the metal layer is patterned by etching or the like, for example, tothereby form a wiring pattern in the antenna 4. The antenna 4 isfabricated in this way.

The sheet substrate 41 preferably has a thickness of 15 μm to 50 μm.

The thickness T of the metal layer is preferably 5 μm to 50 μm, and morepreferably 5 μm to 20 μm. As an example of the structure of the antenna4, the following configuration can be used. Specifically, in theconfiguration, for example, a PET film having a thickness of 38 μm isused as the sheet substrate 41, the front surface of the sheet substrate41 where the coupling coil portion 4A, the main coil portion 4B, thefirst electrode 42 a, and the like are formed is provided with alamination of an aluminum foil (aluminum layer) having a thickness of 10μm (thickness of not more than 30 μm), and the base laminated with thealuminum foil is etched to form the wiring pattern described above.Alternatively, the following configuration can also be used.Specifically, in the configuration, the surface on the opposite side ofthe front surface, i.e. the back surface of the sheet substrate 41,where the second electrode 42 b, the wiring Tb, and the like are formed,is provided with a lamination of an aluminum foil (aluminum layer)having a thickness of 30 μm, and the base laminated with the aluminumfoil is etched to form the wiring pattern described above.

To fabricate the dual IC card 1 having the above-describedconfiguration, the IC module 3 and the antenna 4 are individuallyfabricated first. Then, the antenna 4 is sandwiched between syntheticresin sheets for forming the card body 2, and processing such ashot-press laminating or bonding processing, is performed to integratethe antenna 4 and the synthetic resin sheets.

Then, the sheet integrated in this way is punched into a shape of a cardbody 2.

Then, the front surface 2 e of the card body 2 is subjected to millingprocessing, for example, to form the IC module accommodating portion 21.

Then, for example, an adhesive such as a hot-melt sheet and the ICmodule 3 are arranged in the IC module accommodating portion 21 to bondthe IC module 3 in the IC module accommodating portion 21.

When forming an embossed portion, such as character strings or the like,in the first and second embossed areas 5 and 6, embossing-process isfurther performed. In this case, portions overlapping with the first andsecond embossed areas 5 and 6 in the coupling coil portion 4A and themain coil portion 4B each include a wiring whose line width is madelarger than the height of the character strings. Therefore, if a stressis imposed on the wiring during the embossing-process, the wiring is notbroken.

In this way, the dual IC card 1 is fabricated.

Next, an operation of the dual IC card 1 will be described.

In fabricating the dual IC card 1, a setup for contactless communicationis performed first. Specifically, a resonance frequency is set so as tosatisfy the characteristics of the IC chip 33 to be used and thecommunication characteristics defined by the standards or the like, andan inductance of the antenna 4 and a capacitance of the capacitiveelement 42 are determined.

Then, a wiring pattern of the antenna 4 is designed on the basis of theshape, layout position, or the like of the IC module 3 so as to beaccommodated in a space of the card body 2.

The antenna 4 of the dual IC card 1 is not directly connected to the ICchip 33. Accordingly, a load of the resonant circuit becomes smallerthan that in the case where the antenna is directly connected to the ICchip 33. Thus, the high Q value of the resonant circuit is increased inthe dual IC card 1 as a whole.

On the other hand, an excessively large Q value creates an excessivelynarrow resonance band. Therefore, if a resonance frequency varies due tofabrication errors of the antenna 4, for example, there is a concernthat communication quality is impaired.

Accordingly, to optimize the Q value of the antenna 4, an appropriateelectrical resistance is required to be set in the antenna 4.

To increase the resistance of the antenna 4, a method of increasing thelength of the wiring, or a method of decreasing the cross-sectional areaof the wiring may be used.

However, when the number of times with which the coil is looped isincreased to thereby increase the length of the wiring, the inductanceis also varied. Therefore, desired communication characteristics can nolonger be obtained. Further, the electrical resistance can be changedonly on the looped-number-of-times basis. Therefore, it is difficult tofinely adjust the resistance.

The line width of the wiring in an area overlapping with the first orsecond embossed area 5 or 6 cannot be decreased. Therefore, there is alimitation in increasing the number of times with which the coil islooped.

If the cross-sectional area of the wiring is decreased, strength againstan external force is also decreased. This raises a problem thatdisconnection easily occurs in the process of fabricating the card or inusing the card.

In the first embodiment, the card includes the resistance-increasingportion B3 a. Therefore, the electrical resistance can be increased byappropriately setting the wiring pattern of the resistance-increasingportion B3 a and changing the line length.

Specifically, the equivalent coil wiring B3′ is used in place of thecoil wiring B3 to design a wiring pattern and calculate an inductance ora Q value. If the Q value is excessively large, an electrical resistanceto be increased is calculated, and a line length of theresistance-increasing portion B3 a corresponding to the increase of theelectrical resistance is calculated. Then, a rectangular wave-likewiring pattern for realizing the line length is calculated.

In this case, since the inductance is the same as that of the equivalentcoil wiring B3′, the need to redesign the resonant circuit iseliminated, and an efficient designing can be realized.

In this way, the dual IC card 1 of the first embodiment can realize aconfiguration that achieves a resonant circuit having a small Q valuewhile the IC module 3 is electromagnetically coupled to the antenna 4.Accordingly, stable communication quality can be obtained.

In addition, since designing is facilitated, time and cost involved indesigning can be reduced.

[First Modification]

A dual IC card according to a first modification of the first embodimentwill now be described.

FIG. 6 is a schematic diagram of a wiring pattern illustrating aresistance-increasing portion in the dual IC card according to the firstmodification of the first embodiment of the present invention. SinceFIG. 6 is a schematic diagram, the line width of the wiring is notshown, but only the center line of the line width is shown by the solidline (the same applies to FIGS. 7 to 10 below).

As shown in FIG. 1, a dual IC card 1A according to the presentmodification includes a resistance-increasing portion 51 (first bentpattern) in place of the resistance-increasing portion B3 a of the dualIC card 1 according to the first embodiment.

The following description is focused on the configurations differentfrom those of the first embodiment. In the present modification,components identical with or equivalent to those of the first embodimentare designated with identical reference signs to omit commondescription.

As shown in FIG. 6, the resistance-increasing portion 51 is a wiringportion having a wiring pattern of a sinusoidal wave. The sinusoidalwave oscillates centering on the straight line O formed between thepoints P1 and P2 and has an amplitude A, a wavelength k, and a linewidth Wa (not shown in FIG. 6). In the wiring pattern, the sinusoidalwave continues by an integral multiple of the wavelength λ.

Although FIG. 6 exemplifies the case of five waves as an example, thewiring pattern of the resistance-increasing portion 51 is not limited tothe case of FIG. 6. The number of waves, the amplitude A (A≤ha−Wa/2),the wavelength k, and the line width Wa can be set in accordance with anelectrical resistance value necessary for the antenna 4.

The line length of the resistance-increasing portion 51 can becalculated by a line integral of a function representing the sinusoidalwave.

According to the resistance-increasing portion 51, as in theresistance-increasing portion B3 a according to the first embodiment,the sum of the opening area decrease S2 and the opening area increase S1in the coil wiring B3 is ensured to be zero. Accordingly, the inductanceof the coil wiring B3 in the present modification does not differ fromthe inductance of the equivalent coil wiring B3′. On the other hand,since the line length of the resistance-increasing portion 51 is longerthan the distance L_(O), only the electrical resistance is increased.

[Second Modification]

A dual IC card according to a second modification of the firstembodiment will now be described.

FIG. 7 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the secondmodification of the first embodiment of the present invention.

As shown in FIG. 1, a dual IC card 1B according to the presentmodification includes a resistance-increasing portion 52 (first bentpattern) in place of the resistance-increasing portion B3 a of the dualIC card 1 according to the first embodiment.

The following description is focused on the configurations differentfrom those of the first embodiment. In the present modification,components identical with or equivalent to those of the first embodimentare designated with identical reference signs to omit commondescription.

As shown in FIG. 7, the resistance-increasing portion 52 is a syntheticwave in which a plurality of sinusoidal waves are superimposed centeringon the straight line O formed between the points P1 and P2. Similar tothe resistance-increasing portion B3 a, the resistance-increasingportion 52 is a wiring pattern in which the sum of the opening areadecrease S2 and the opening area increase 51 in the coil wiring B3 isensured to be zero.

The amplitudes, waves, and phases of the sinusoidal waves to besuperimposed are not particularly limited, and the number of sinusoidalwaves to be superimposed is not particularly limited either.

The line length of the resistance-increasing portion 52 can becalculated by a line integral of a function representing the waveform.

According to the resistance-increasing portion 52, similar to theresistance-increasing portion B3 a according to the first embodiment,the sum of the opening area decrease S2 and the opening area increase 51in the coil wiring B3 is ensured to be zero. Accordingly, the inductanceof the coil wiring B3 in the present modification does not differ fromthe inductance of the equivalent coil wiring B3′. On the other hand,since the line length of the resistance-increasing portion 52 is longerthan the distance L_(O), only the electrical resistance is increased.

[Third Modification]

A dual IC card according to a third modification of the first embodimentwill now be described.

FIG. 8 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the thirdmodification of the first embodiment of the present invention.

As shown in FIG. 1, a dual IC card 1C according to the presentmodification includes a wiring portion 53 in place of theresistance-increasing portion B3 a of the dual IC card 1 according tothe first embodiment.

As shown in FIG. 8, the wiring portion 53 is formed of a thin lineportion 53A, a resistance-increasing portion 53B (first bent pattern),and a thin line portion 53C.

The following description is focused on the configurations differentfrom those of the first embodiment. In the present modification,components identical with or equivalent to those of the first embodimentare designated with identical reference signs to omit commondescription.

The thin line portion 53A is a wiring portion having a line width Wa andformed along the straight line O from the point P1 at an end of thethick line portion B3 c to a point Q1 on the straight line O locatedhalfway of the wiring portion 53.

The resistance-increasing portion 53B is a wiring portion having awiring pattern of a sinusoidal wave. The sinusoidal wave oscillatescentering on the straight line O that links the point Q1 and a point Q2positioned between the point Q1 and a point P2 on the straight line O,and has an amplitude A, a wavelength λ′ (λ′<λ), and a line width Wa (notshown in FIG. 8). In the wiring pattern, the sinusoidal wave continuesby an integral multiple of the wavelength λ′.

FIG. 8 exemplifies the case of five waves as an example. However, thewiring pattern of the resistance-increasing portion 53B is not limitedto this. The number of waves, the amplitude A (A≤ha−Wa/2), thewavelength λ′, and the line width Wa can be set in accordance with anelectrical resistance value necessary for the antenna 4.

The line length of the resistance-increasing portion 53B can becalculated by a line integral of a function representing the sinusoidalwave.

The thin line portion 53C is a wiring portion having a line width Wa andformed along the straight line O from the point Q2 to the point P2 at anend of the thick line portion B3 d.

Thus, in the resistance-increasing portion 53B of the dual IC card 1Caccording to the present modification, there is a change in thewavelength of the resistance-increasing portion 51 which is formed inthe range of the length L_(O) along the coil wiring path (directconnection) of the first modification. The resistance-increasing portion53B is formed in a range of a length L_(53B) along the coil wiring path,the length being equal to the distance between the points Q1 and Q2(L_(53B)<L_(O)).

Thus, as long as a necessary increase of the electrical resistance isensured, the resistance-increasing portion may be provided partially ona straight portion of the coil wiring path.

According to the resistance-increasing portion 53B, similar to theresistance-increasing portion 51 of the first modification, the sum ofthe opening area decrease S2 and the opening area increase S1 in thecoil wiring B3 is ensured to be zero. Accordingly, the inductance of thecoil wiring B3 in the present modification does not differ from theinductance of the equivalent coil wiring B3′. On the other hand, sincethe line length of the resistance-increasing portion 53B is longer thanthe length L_(53B), only the electrical resistance is increased.

[Fourth Modification]

A dual IC card according to a fourth modification of the firstembodiment will now be described.

FIG. 9 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the fourthmodification of the first embodiment of the present invention.

As shown in FIG. 1, a dual IC card 1D according to the presentmodification includes a wiring portion 53 in place of theresistance-increasing portion B3 a of the dual IC card 1 according tothe first embodiment.

As shown in FIG. 9, the wiring portion 54 is formed of a thin lineportion 54A, a resistance-increasing portion 54B, and a thin lineportion 54C.

The following description is focused on the configurations differentfrom those of the first embodiment. In the present modification,components identical with or equivalent to those of the first embodimentare designated with identical reference signs to omit commondescription.

The thin line portion 54A is a wiring portion having a line width Wa andformed along the straight line O from the point P1 at an end of thethick line portion B3 c to the point Q1 halfway of the wiring portion 53on the straight line O. The position of the point Q1 may be or may notbe the same as the position of the point Q1 of the third modification.

The resistance-increasing portion 54B is a wiring portion havingrectangular wave-like wiring patterns meandering in directions along thestraight line O by linking the point Q1 and the point Q2 positionedbetween the points Q1 and P2 on the straight line O.

FIG. 9 exemplifies, as an example, the case where theresistance-increasing portion 54B is formed of an end wiring 55, ameandering wiring 56 (second bent patterns), and an end wiring 57.

The end wiring 55 is an L-shaped wiring portion extending to the outerside of the coil wiring B3 along they direction from the point Q1 by adistance 3×y0 (distance threefold of y0), further extending along the xdirection toward the point Q2 (+x direction) by a distance x0, andreaching a point U1 that is an end.

The meandering wiring 56 extends along the x direction from the point U1that is an end of the end wiring 55 (path start point) toward the pointQ2 (+x direction) by a distance x1, further extends to the inner side ofthe coil wiring B3 along the y direction by a distance y0, returns alongthe x direction toward the point Q1 by the distance x1, further extendsto the inner side of the coil wiring B3 along the y direction by thedistance y0 (pitch y0), and reaches an end (path end point) of a singlepath pattern configuring the meandering wiring 56. The meandering wiring56 is formed by repeating such a single path pattern 3.5 times (by 3.5reciprocations) which extends from the path start point to the path endpoint. Thus, the meandering wiring 56 is configured to have rectangularwave patterns such as the ones in which waveforms are spaced apart atthe pitch y0 in the y direction while each waveform has a width x1 alongthe straight line O.

In other words, in the outside of the coil wiring B3 with the straightline O inclusive, there are formed wiring patterns meandering two timesalong a path pattern having a y-direction spacing y0 and an x-directiondistance x1, whereas in the inside of the coil wiring B3 with thestraight line O exclusive, there are formed wiring patterns meandering1.5 times along a path pattern having the y-direction spacing y0 and thex-direction distance x1.

The meandering wiring 56 is extended from the point U1 to a point U2.Herein, the point U2 is spaced apart from the point Q1 by x0+x1 in the xdirection, and spaced apart from the straight line O toward the innerside of the coil wiring B3 by a distance 3×y0.

The end wiring 57 is an L-shaped wiring portion extending along the xdirection from the point U2 toward the point Q2 (+x direction) by adistance x0, and extending along the y direction toward the outer sideof the coil wiring B3 by a distance 3×y0.

With this configuration, the resistance-increasing portion 54Bconfigures wiring patterns that are 180° rotationally symmetric about amidpoint QM of a line segment Q1-Q2 on the straight line O. In themeandering wiring 56, the sum of the opening area increase and decreaseS1 and S2 of the coil wiring B3 is ensured to be zero.

The thin line portion 54C is a wiring portion having a line width Wa andformed along the straight line O from the point Q2 to the point P2 at anend of the thick line portion B3 d.

In the resistance-increasing portion 54B having such a configuration,due to the symmetry of the resistance-increasing portion 54B, the sum ofthe opening area decrease S2 and the opening area increase S1 in thecoil wiring B3 is ensured to be zero, similar to theresistance-increasing portion B3 a according to the first embodiment.Accordingly, the inductance of the coil wiring B3 in the presentmodification does not differ from the inductance of the equivalent coilwiring B3′. On the other hand, since the line length of theresistance-increasing portion 54B is longer than the distance 2·x0+x1,only the electrical resistance is increased.

The patterns of the wiring configuring the meandering wiring 56 of theresistance-increasing portion 54B of the present modification correspondto second bent patterns which are arranged parallel to the directconnection in a multiple manner.

[Fifth Modification]

A dual IC card according to a fifth modification of the first embodimentwill now be described.

FIG. 10 is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the fifthmodification of the first embodiment of the present invention.

As shown in FIG. 1, a dual IC card 1E according to the presentmodification includes a wiring portion 58 in place of theresistance-increasing portion B3 a of the dual IC card 1 according tothe first embodiment.

As shown in FIG. 10, the wiring portion 58 is a wiring pattern in whichthe resistance-increasing portion 54B in the wiring portion 54 of thefourth variation is replaced by three resistance-increasing portions59A, 59B, and 59C (first bent pattern).

The following description is focused on the configurations differentfrom those of the first embodiment and the fourth modification. In thepresent modification, components identical with or equivalent to thoseof the first embodiment and the fourth modification are designated withidentical reference signs to omit common description.

The resistance-increasing portion 59A is a wiring portion which isprovided with a spiral wiring pattern having a line width Wa and formedof spiral wirings 59 a and 59 b.

The spiral wiring 59 a is a wiring portion formed of an angular spiralpattern in which the wirings parallel to the x and y directions arecombined and looped 1.5 times from the outer side toward the inner sideof the coil wiring B3, sandwiching the straight line O. The looping isprovided from the point Q1 to a point V1 positioned between the pointsQ1 and Q2 on the straight line O.

The volute wiring 59 b is a wiring portion formed of an angular spiralpattern that is 180° rotationally symmetric about the point V1 with thespiral wiring 59 a.

One end of the volute wiring 59 b coincides with the point V1, and theother end of the volute wiring 59 b coincides with a point V2. The pointV2 is point-symmetric, on the straight line O, about the point V1 withthe point Q1.

The distance L59 between the points Q1 and V2 is one-third of thedistance between the points Q1 and Q2.

The resistance-increasing portion 59B corresponds to a wiring patternprovided by translating the resistance-increasing portion 59A along thestraight line O by the distance L59. The resistance-increasing portion59B has a start point V2, a symmetry center point V3, and an end pointV4 which correspond to the start point Q1, the symmetry center point V1,and the end point V2 of the resistance-increasing portion 59A,respectively.

The resistance-increasing portion 59C is a wiring pattern provided bytranslating the resistance-increasing portion 59B along the straightline O by the distance L59, and has the start point V4, a symmetrycenter point V5, and the end point Q2, which correspond to the startpoint V2, the symmetry center point V3, and the end point V4 of theresistance-increasing portion 59B, respectively.

With this configuration, the resistance-increasing portions 59A, 59B and59C configure wiring patterns that are 180° rotationally symmetric aboutthe respective center symmetry points V1, V3, and V5 positioned on thestraight line O. In each of the resistance-increasing portions 59A, 59Band 59C, the sum of the opening area increase and decrease S1 and S2 inthe coil wiring B3 is ensured to be zero.

Each wiring pattern of the resistance-increasing portions 59A, 59B and59C corresponds to the first bent pattern intersecting the directconnection a plurality of times.

In each of the resistance-increasing portions 59A, 59B and 59C havingsuch a configuration, the sum of the opening area decrease S2 and theopening area increase S1 in the coil wiring B3 is ensured to be zero.Accordingly, the inductance of the coil wiring B3 in the presentmodification does not differ from the inductance of the equivalent coilwiring B3′. On the other hand, since the line length of each of theresistance-increasing portions 59A, 59B and 59C is longer than thedistance L59, only the electrical resistance is increased.

The first embodiment and the modifications thereof described so far havedealt with the case where the resistance-increasing portion is formed ina wiring portion which is located along the first long side portion 2 aof the outermost third looping of the main coil portion 4B. As long asthe resistance-increasing portion is provided in an area(emboss-processing-prohibited area) that does not overlap with the firstand second embossed areas 5 and 6, which serve as theemboss-processing-enabled areas, the resistance-increasing portion canbe provided at any position on the main coil portion 4B.

In the first embodiment, an embossing-process-prohibited area isprovided, extending along the first long side portion 2 a, which is onelong side, and extending from the card center, which corresponds toapproximately a half position in the short side direction of the dual ICcard 1, to the vicinity of the first long side portion 2 a. Also,embossing-process-enabled areas, i.e. the first and second embossedareas 5 and 6, are provided in the vicinity of and extending along thesecond long side portion 2 b, which is the other long side.

Therefore, for example, a resistance-increasing portion can be providedin place of the thin line portion B1 c, in theembossing-process-prohibited area.

Furthermore, for example, a resistance-increasing portion can beprovided partially in an area of each of the thick line portions B3 cand B3 d, the lateral wiring portions B2 c and B2 d, the thin lineportion B1 c, and the lateral wiring portion B1 d, the area overlappingwith the embossing-process-prohibited area.

However, in the case where the resistance-increasing portion is providedon the coil wiring path (direct connection) extending along andpositioned in the vicinity of the first long side portion 2 a, theresistance-increasing portion is not provided with anembossing-process-enabled area. Therefore, this case is more preferablebecause the length of the resistance-increasing portion can be increasedand the increase of the resistance can be enhanced.

If a resistance-increasing portion is provided in a portion other thanthe outermost of the main coil portion, the line width of the outermostwiring is preferably set to be not less than 0.4 mm.

FIG. 11A shows a wiring pattern of a sixth modification which is anexample of such a configuration.

FIG. 11A is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the sixthmodification of the first embodiment of the present invention.

As shown in FIG. 11A, in the present modification, the outermost of themain coil portion is formed of a thick line portion B4 a having a linewidth W4 a of not less than 0.4 mm, with the resistance-increasingportion B3 a having a line width W of less than 0.4 mm being arranged onthe inner side of the thick line portion B4 a.

In the outermost of the main coil portion, which is most likely to beexposed to an etching solution in the antenna fabricating process, thecoil is easily disconnected. However, according to the presentmodification, since the thick line portion B4 a is provided outermost,the coil can be prevented from being disconnected in the etching processand the resistance value can be efficiently increased by theresistance-increasing portion B3 a having a line width of less than 0.4mm and provided on the inner side of the thick line portion B4 a.

Similarly, the resistance value with line width can be efficientlyincreased in the case where a resistance-increasing portion is providedon the inner side of the coupling coil portion as will be describedlater.

The first embodiment and the modifications thereof describe the casewhere the resistance-increasing portion is formed in the main coilportion 4B. Alternatively, the resistance-increasing portion can beprovided at any position on the coupling coil portion 4A as long as theresistance-increasing portion is formed in theembossing-process-prohibited area.

The above-described first embodiment and the modifications thereofdescribe the case where the resistance-increasing portion is formed inthe embossing-process-prohibited area. However, as long as theresistance-increasing portion is formed in an area not overlapping withthe embossed portion formed by embossing-process, theresistance-increasing portion can be arranged in theembossing-process-enabled area at an appropriate position on the coilwiring path (the direct connection) in the coupling coil portion 4A andthe main coil portion 4B.

The first modification describes the case where the wiring pattern ofthe resistance-increasing portion 51 is a sinusoidal wave pattern.However, the wiring pattern of the resistance-increasing portion 51 isnot limited to an exact sinusoidal wave pattern, but an appropriate wavepattern where the opening area increase S1 is equal to the opening areadecrease S2 can be used. For example, wave patterns that can be usedinclude a triangular wave pattern having pointed peaks, a sawtooth wavepattern, or a wave pattern formed by concatenating rectangular waveswith rounded corners, i.e., U-shaped waves.

The first embodiment and the modifications thereof describe the casewhere one resistance-increasing portion is provided in the antenna 4.Alternatively, a plurality of resistance-increasing portions may beprovided in the antenna 4.

When a plurality of resistance-increasing portions are provided in theantenna 4, increase of the resistance may be different between theresistance-increasing portions. In this case, the sum of the electricalresistances of the resistance-increasing portions is preferably set tobe larger by a factor of two or more than the electrical resistance of awiring having a cross-sectional area and formed of a material, which areboth the same as those of the wiring (direct connection) extending alongthe coil wiring path.

The first embodiment and the modifications thereof describe the casewhere the width and cross-sectional area of the line in theresistance-increasing portion are constant. However, the width andcross-sectional area of the line in the resistance-increasing portionare not limited to be constant but may be varied along the line. In thiscase, the line width of the equivalent coil wiring used for calculatinga preferable electrical resistance is equal to a mean value of the linewidths of the resistance-increasing portion, and the cross-sectionalarea of the equivalent coil wiring used for calculating a preferableelectrical resistance is equal to a mean value of the cross-sectionalareas of the resistance-increasing portion. By using the mean value ofthe line widths and the mean value of the cross-sectional areas, theelectrical resistance of the equivalent coil wiring is calculated.

When the line width in the resistance-increasing portion is partiallychanged, the line width of the outermost wiring is preferably not lessthan 0.4 mm.

FIG. 11B shows a wiring pattern of a seventh modification which is anexample of such a configuration.

FIG. 11B is a schematic diagram illustrating a wiring pattern of aresistance-increasing portion in a dual IC card according to the seventhmodification of the first embodiment of the present invention.

As shown in FIG. 11B, in the present modification, a large width portionBout having a line width Wout of not less than 0.4 mm is formed on theoutermost side of the resistance-increasing portion B3 a locatedoutermost of the main coil portion. In this configuration, theresistance-increasing portion B3 a positioned on the inner side relativeto the large width portion Bout has a line width W less than 0.4 mm.

In an outermost of the main coil portion, which is most likely to beexposed to an etching solution in the antenna fabricating process, thecoil is easily disconnected. However, according to the presentmodification, since the large width portion Bout is provided in theoutermost periphery, the coil can be prevented from being disconnectedin the etching process and the resistance value can be efficientlyincreased by the portion of the resistance-increasing portion B3 ahaving the line width of less than 0.4 mm and provided on the inner sideof the large width portion Bout.

The first embodiment and the modifications thereof describe the casewhere the line width in the resistance-increasing portion is madedifferent from that of other coil wirings to thereby increase theelectrical resistance per unit line length. Alternatively, theelectrical resistance per unit line length in the resistance-increasingportion may be made equal to that of other coil wirings.

The electrical resistance per unit line length in theresistance-increasing portion can be changed by changing thecross-sectional area. Besides the line width, for example, the thicknessof the wiring may be changed to ensure the increase of the electricalresistance per unit line length more than other wirings.

The first embodiment and the modifications thereof describe the casewhere the resistance-increasing portion is provided on the linear coilwiring path (direct connection). Alternatively, theresistance-increasing portion may be provided on a curved directconnection. For example, when the direct connection is in an arc shape,the increase and the decrease in the coil opening area caused by theresistance-increasing portion is calculated using the arc line as aboundary.

The third to fifth modifications describe the case where theresistance-increasing portion is provided halfway of the straightportion of the angular and spiral coil wiring path. Alternatively, theresistance-increasing portion may be provided at an end of the straightportion. For example, it may be so configured that the thin lineportions 53A and 54A or the thin line portions 53C and 54C are removedfrom the third to fifth modifications.

Second Embodiment

With reference to FIGS. 12 to 14B, a second embodiment of a dual IC cardaccording to the present invention will be described.

In FIGS. 12 to 14B, components identical with those of the firstembodiment are designated with identical reference signs to omit orsimplify description.

As shown in FIG. 13, the main coil portion 4B in the second embodimentis forms a coil opening in an area adjacent to the IC module 3 toperform reception/transmission in contactless communication with anexternal machine and receive power supply from the external machine. Themain coil portion 4B is connected to an end of the thick line portion A5b of the coupling coil portion 4A, the end being close to the secondshort side portion 2 d. In the second embodiment, the main coil portion4B is configured by being looped three times, with the line width beingmade different depending on where the wiring is provided.

A coil wiring B13 that configures an outermost third looping of the maincoil portion 4B is formed of a thick line portion B13 b having a linewidth W3 b and routed in the x direction at a position contiguous withthe second long side portion 2 b, a thick line portion B13 d having aline width W3 d (W<W3 d<W3 b) and routed in the y direction at aposition contiguous with the second short side portion 2 d, a thick lineportion B13 a having a line width W3 a (W<W3 a<W3 d) and routed in the xdirection at a position contiguous with the first long side portion 2 a,and a thick line portion B13 c routed in they direction at a positioncontiguous with the coupling coil portion 4A.

Similar to the thick line portion B13 d, the line width W3 d is impartedto the thick line portion B13 c at a position close to the first longside portion 2 a. Similar to the thick line portion A4 b, an increasedline width W3 b is imparted to a portion of the thick line portion B13 cparallel to the thick line portion A4 b of the coupling coil portion 4A.

A coil wiring B12 that configures second looping of the main coilportion 4B is routed along the inner side of the coil wiring B13 fromthe end of the thick line portion B13 c close to the second long sideportion 2 b. The coil wiring B12 is formed of a thick line portion B12 bhaving a line width W3 b and extending along the thick line portion B13b, a lateral wiring portion B12 d extending along the thick line portionB13 d, a thin line portion B12 a having a line width W and extendingalong the thick line portion B13 a, and a lateral wiring portion B12 cextending along the thick line portion B13 c.

The line width W3 b is imparted to both of the portions of the lateralwiring portions B12 d and B12 c parallel to the thick line portion A4 bof the coupling coil portion 4A and close to the second long sideportion 2 b. The line width W is imparted to both of the portions of thelateral wiring portions B12 d and B12 c close to the first long sideportion 2 a. The portions having such different line widths are mutuallylinked via an intermediate wiring portion having a wiring width equal toor more than the line width W.

In the second embodiment, these intermediate wiring portions are formedat positions closer to the first long side portion 2 a than to theextension line Lb of the second side surface portion 22 b. Accordingly,on the extension line Lb, the line width is W3 b in all of theintermediate wiring portions.

A coil wiring B11 that configures first looping of the main coil portion4B is routed along the inner side of the coil wiring B12 from the end ofthe lateral wiring portion B12 c close to the second long side portion 2b. The coil wiring B11 is formed of a thick line portion B11 b having aline width W3 b and extending along the thick line portion B12 b, alateral wiring portion B11 d extending along the lateral wiring portionB12 d, a thin line portion B11 a having a line width W and extendingalong the thin line portion B12 a, and a thin line portion B11 c havinga width W and extending along the lateral wiring portion B12 c.

A portion of the lateral wiring portion B11 d parallel to the thick lineportion A4 b of the coupling coil portion 4A has a line width W3 b. Aportion of the lateral wiring portion B11 d close to the first long sideportion 2 a has a line width W. These portions having different linewidths are mutually linked via an intermediate wiring portion having awiring width equal to or more than the line width W.

In the second embodiment, these intermediate wiring portions are formedat positions closer to the first long side portion 2 a than to theextension line Lb of the second side surface portion 22 b. Accordingly,on the extension line Lb, the line width is W3 b in all of theintermediate wiring portions.

The thin line portion B11 c extends halfway of the portion of thelateral wiring portion B12 c having a line width W, and terminates. Thistermination portion is electrically connected to the capacitive element42 via the wiring Ta.

The distance between the thin line portion B11 a positioned close to thethick line portion B13 a and the capacitive element 42 in the secondembodiment is longer than the distance between the thin line portion B1a positioned close to the main coil portion 4B and the capacitiveelement 42 in the first embodiment. In other words, a larger area isformed between the thin line portion B11 a and the capacitive element 42in the second embodiment than in the first embodiment.

An operation of the dual IC card 1 will be described.

FIGS. 14A and 14B are schematic diagrams each illustrating a state wherethe dual IC card according to the second embodiment of the presentinvention has been bent and deformed. Since FIGS. 14A and 14B areschematic diagrams, members other than the card body 2 are omitted.

The dual IC card 1 is formed of a rectangular thin plate and thus isdeformed when receiving an external force while being used. Depending onthe magnitude of an internal stress of the dual IC card 1, in wiring maybe disconnected.

Particularly, since the dual IC card 1 is provided with the IC moduleaccommodating portion 21 that is a recess for embedding the IC module 3,a stress concentration occurs in a portion where the thickness of thecard body 2 drastically changes.

For example, as shown in FIG. 14A, if the dual IC card 1 is bent in alongitudinal direction, the dual IC card 1 as a whole is curved and abending stress occurs inside. This bending stress caused by an externalforce is maximized in the vicinity of the center O of the dual IC card1, and gradually decreases from the center O toward the first and secondshort side portions 2 c and 2 d.

Stress concentration occurs in a corner portion Pc which is formed bythe third side surface portion 22 c and the bottom of the first holeportion 22, and in a corner portion Pd which is formed by the fourthside surface portion 22 d and the bottom of the first hole portion 22.The stress occurring in the corner portion Pd which is close to thecenter of the dual IC card 1 is larger than the stress occurring in thecorner portion Pc which is close to the first short side portion 2 c.

As shown in FIG. 14B, a bending stress similarly occurs inside the dualIC card 1 in the case where the dual IC card 1 is bent in a short-lengthdirection. This bending stress caused by an external force is maximizedin the vicinity of the center O of the dual IC card 1, and graduallydecreases from the center O toward the first and second long sideportions 2 a and 2 b.

If the deflections at both ends (first and second long side portions 2 aand 2 b) are equal to the deflections due to the bending in thelongitudinal direction, a bending stress by the bending across theshorter dimension is larger than the bending stress caused by thebending in the longitudinal direction.

Stress concentration occurs in a corner portion Pa which is formed bythe first side surface portion 22 a and the bottom of the first holeportion 22, and in a corner portion Pb which is formed by the secondside surface portion 22 b and the bottom of the first hole portion 22.The stress occurring in the corner portion Pb which is close to thecenter of the dual IC card 1 is larger than the stress occurring in thecorner portion Pa which is close to the first long side portion 2 a.

Thus, the magnitude of the bending stress caused by the stressconcentration in the IC module accommodating portion 21 is maximized inthe corner portion Pb, and bending stresses occurring in the cornerportions Pa, Pd, and Pc decrease in this order.

Accordingly, if the dual IC card 1 is bent, a high stress field due tothe stress concentration is formed particularly between the cornerportion Pb and the back surface 2 f. This high stress field propagatesin a specific range in the vicinity of the corner portion Pb, whichleads to the increase of the stress occurring in an area located on theextension line of the corner portion Pb and in the vicinity of thecorner portion Pb.

The stress concentration also occurs in the corner portions Pa, Pd, andPc where, however, the bending stress due to the external force issmall. Accordingly, there is generated no stress field against whichreinforcement is particularly required.

Actually, the inventor conducted a durability test on a conventionaldual IC card in which a wiring having a line width of 0.4 mm wasarranged immediately below the corner portions. When there was abreakage in the looped wiring provided overlapping with the cornerportion Pb or overlapping with a position on the extension line of thecorner portion Pb, there was no breakage in the wirings provided atpositions overlapping with the corner portions Pa, Pd, and Pc.

In the dual IC card 1 according to the second embodiment, the couplingcoil portion 4A is located outside the IC module accommodating portion21. Accordingly, no wiring is located immediately below the cornerportions Pb, Pa, Pd and Pc. Thus, the dual IC card 1 according to thesecond embodiment is configured to be less influenced by the high stressfield caused by a stress concentration.

The coil wiring A1 provided along the corner portion Pb where thelargest stress occurs corresponds to the thick line portion A1 b havinga line width of not less than 1 mm. Therefore, wiring durability of thecoil wiring A1 is improved, and thus the coil wiring A1 is preventedfrom being disconnected when the antenna 4 or the IC moduleaccommodating portion 21 is displaced due to fabrication variations tocause the coil wiring A1 to partially overlap with the corner portionPb.

Furthermore, the line width transition portions Atc and Atd are providedat positions intersecting the extension line Lb of the second sidesurface portion 22 b. In this case, the line widths We and Wdoverlapping with the extension line Lb are rendered be not less than 1mm. Accordingly, the coil wiring A1 can be prevented from beingdisconnected caused by a high stress field generated on the extensionline of the corner portion Pb.

Being spaced apart from the corner portion Pb, the coil wiring A2 is notinfluenced by a stress field caused by the stress concentration if thecoil wiring A2 is provided on the extension line of the corner portionPb. Accordingly, there is no risk of disconnection in the coil wiring A2if the coil wiring A2 has a line width W.

The stress concentration at the first hole portion 22 has so far beendescribed. A stress concentration similarly occurs in the corner portionwhere the side surface portions intersect the bottom surface portion inthe second hole portion 23. However, the second hole portion 23 isformed inside the first hole portion 22 penetrating through the sheetsubstrate 41. Accordingly, no wiring will be located immediately belowthe corner portion. The stress concentration occurs in an area closer tothe back surface 2 f than to the sheet substrate 41. Accordingly, theinfluence of the stress concentration generated in the second holeportion 23 is negligible in the coil wiring A1 formed on a surface ofthe sheet substrate 41, the surface being close to the front surface 2e.

As described above, according to the dual IC card 1, since the couplingcoil portion 4A is arranged outside the IC module accommodating portion21, a failure due to the breakage of the coupling coil portion 4A can beminimized in the event that a bending stress caused by an external forceis generated.

Third Embodiment

With reference to FIGS. 15 to 20, a third embodiment of a dual IC cardaccording to the present invention will be described.

In FIGS. 15 to 20, components identical with those of the first andsecond embodiments are designated with identical reference signs to omitor simplify description.

As shown in FIGS. 15 and 16, a dual IC card 101 includes a plate-likecard body 110 formed with a recess 111, and an IC module 130accommodated in the recess 111.

FIG. 15 is a schematic cross section illustrating the dual IC card 101.In FIG. 15, an antenna 113 described later, which is looped severaltimes, is simplified. In FIG. 16, the antenna 113 and a capacitiveelement 114 in the card body 110 are shown, with only the contour of thecapacitive element 114 being shown as seen through the substrate 112.FIG. 16 shows, by hatching, a second coil segment 152, which isdescribed below.

The card body 110 has a substrate 112, the antenna 113 provided on thesubstrate 112, the capacitive element 114 connected (electricallyconnected) to the antenna 113, and a card base 115 sealing the substrate112, the antenna 113 and the capacitive element 114.

The substrate 112 is formed using an insulative material, such as PET(polyethylene terephthalate), polyethylene naphthalate (PEN), or thelike, into a rectangular shape in plan view (see FIG. 16).

At a position close to a short side 112 c of the substrate 112, anaccommodating hole 112 d penetrating the substrate 112 in a thicknessdirection D is formed. The accommodating hole 112 d is formed into arectangular shape, in plan view, with its sides being parallel to shortor long sides of the substrate 112. The thickness of the substrate 112is, for example, 15 to 50 μm (micrometers).

The antenna 113 has a coupling coil 118 for electromagnetic couplingwith a connecting coil 131, described later, of the IC module 130, and amain coil 119 connected to the coupling coil 118 for performingcontactless communication with an external contactless machine, such asa reader/writer (now shown). The coupling coil 118 is located in an areaR11 in FIG. 16 and the main coil 119 is located in an area R12 adjacentto the area R11. At a position on the substrate 112 closer to a longside 112 e than to the accommodating hole 112 d, an embossed area R13 isprovided so that an emboss can be formed based on a standard of IC cards(X 6302-1: 2005 (ISO/IEC 7811-1: 2002)).

In this example, as shown in FIGS. 16 and 17, the coupling coil 118 hasa first coil segment 151 and the second coil segment 152. The first coilsegment 151 is provided to the first surface 112 a of the substrate 112where an opening 111 a (see FIG. 15) of the recess 111 is provided. Thesecond coil segment 152 is provided to the second surface 112 b of thesubstrate 112.

The first coil segment 151 is formed into a spiral shape, and loopedfive times around the IC module 130, or the recess 111, when viewed inthe thickness direction D. The width of an element wire 151 aconfiguring the first coil segment 151 in the embossed area R13 islarger than the width of an element wire 151 b provided in an area otherthan the embossed area R13.

The element wire 151 b located innermost of the first coil segment 151has an end which is provided with a terminal portion 120 having a widthlarger than that of the element wire 151 b and formed into asubstantially circular shape. The terminal portion 120 is formed on thefirst surface 112 a.

When viewed in the thickness direction D shown in FIG. 16, the secondcoil segment 152 is formed surrounding the IC module 130 by being loopedonly once. The element wire 152 a of the second coil segment 152 has afirst end located at a position overlapping with the terminal portion120 of the coupling coil 118 in the thickness direction D. At theposition, a terminal portion 153 is provided, with a width being largerthan that of the element wire 152 a and a shape being substantiallycircular. The second coil segment 152 is entirely arranged in an areaother than the embossed area R13. The terminal portion 120 of the firstcoil segment 151 and the terminal portion 153 of the second coil segment152 are electrically connected by performing a known crimping processingor the like. The capacitive element 114 is serially connected betweenthe coupling coil 118 and the main coil 119.

In FIG. 15, the second coil segment 152, which is formed surrounding theIC module 130 is formed outside the IC module 130, may be formedoverlapping with the IC module 130.

As shown in FIGS. 16 and 17, the element wire 151 b located innermost ofthe first coil segment 151 and the element wire 152 a of the second coilsegment 152 overlap with each other around the IC chip 134 by one roundwhen viewed in the thickness direction D. In this example, the width ofthe element wire 151 b of the first coil segment 151 is equal to thewidth of the element wire 152 a of the second coil segment 152.

The element wire 151 b of the first coil segment 151 and the elementwire 152 a of the second coil segment 152, in the portion shown in FIG.17, extend in an extending direction E parallel to the short side 112 cof the substrate 112 described above. In other words, the element wires151 b and 152 a shown in FIG. 17 overlap with each other without beingdisplaced in an orthogonal direction F, which is orthogonal to both ofthe thickness direction D and the extending direction E.

The element wire 151 b located innermost of the first coil segment 151serves as an element wire of the first coil segment 151 nearest to theconnecting coil 131 described later (see FIG. 15).

With the face-to-face arrangement of the element wires 151 b and 152 avia the substrate 112, the capacitor's capacitance of the antenna 113 isincreased. However, as shown in FIG. 16, the second coil segment 152overlaps with the first coil segment 151 only by one round.

As shown in FIG. 16, the main coil 119 is formed into a spiral shape andlooped three times in the area R12. The width of an element wire 119 aconfiguring the main coil 119 in the embossed area R13 is larger thanthe width of an element wire 119 b in an area other than the embossedarea R13. By increasing the width of the element wire 119 a and thewidth of the element wire 151 a mentioned above, the element wires 119 aand 151 a can be prevented from being disconnected when an emboss isformed in the embossed area R13.

The end of the element wire 151 a located outermost of the first coilsegment 151 is connected to an end of the element wire 119 a locatedoutermost of the main coil 119.

Although the line width and the spacing of the element wires 119 b and151 b are not particularly limited, the line width thereof can beapproximately 0.1 mm to 1 mm, and the spacing between the wires can beapproximately 0.1 mm to 1 mm. The element wires 119 a and 151 a in theembossed area R13 can be formed with a line width of approximately 1 mmto 15 mm, and a spacing of approximately 0.1 mm to 1 mm between thewires.

As shown in FIGS. 15 and 16, the capacitive element 114 has an electrodeplate 114 a provided on the first surface 112 a of the substrate 112,and an electrode plate 114 b provided on the second surface 112 b of thesubstrate 112. The electrode plates 114 a and 114 b are located to faceeach other with the substrate 112 being interposed therebetween.

The electrode plate 114 a is connected to an end of the element wire 119b located innermost of the main coil 119.

The electrode plate 114 b is connected to a connecting wiring 121provided on the second surface 112 b. The connecting wiring 121 isconnected to a second end of the element wire 152 a of the second coilsegment 152.

The antenna 113, the capacitive element 114, and the connecting wiring121 can be formed by etching a copper or aluminum foil using aresist-coating method based on generally used gravure printing, forexample, for the substrate 112.

The card base 115 is formed into a rectangular shape in plan view (seeFIG. 16) using an insulative material, including a polyester-basedmaterial such as amorphous polyester, a vinyl chloride-based materialsuch as PVC (polyvinyl chloride), a polycarbonate-based material, PET-G(polyethylene terephthalate copolymer), or the like.

As shown in FIG. 15, the recess 111 mentioned above is formed in thecard base 115. The recess 111 has a first accommodating portion 124formed in a side surface of the card base 115, and a secondaccommodating portion 125 formed in a bottom surface of the firstaccommodating portion 124 and having a diameter smaller than that of thefirst accommodating portion 124. An opening of the first accommodatingportion 124 on the side surface side of the card base 115 serves as theopening 111 a mentioned above.

The substrate 112, the antenna 113, and the capacitive element 114 aresandwiched between a pair of films, and the pair of films are thenintegrated by hot-press laminating or bonding processing. Afterwards,the integrated film may be punched into a shape of a card body.

As shown in FIG. 15, the IC module 130 includes a sheet-like module base133, an IC chip 134 and a connecting coil 131 which are provided on afirst surface of the module base 133, and a plurality of contactterminals (contact terminal portions) 135 provided on a second surfaceof the module base 133.

The IC module 130 may further include an IC resin seal 136.

The module base 133 is formed into a rectangular shape in plan viewusing a material, including glass epoxy or PET (polyethyleneterephthalate). The thickness of the module base 133 is 50 to 200 μm,for example.

As the IC chip 134, a chip with a known configuration having a contactcommunication function and a contactless communication function can beused.

The connecting coil 131 is formed into a spiral shape surrounding the ICchip 134 and the IC resin seal 136. The connecting coil 131 is formed byetching a copper or aluminum foil into a pattern, and has a thickness of5 to 50 μm, for example. The connecting coil 131 configures acontactless terminal portion by electromagnetic coupling with thecoupling coil 118 of the card body 110.

The plurality of contact terminals 135 are formed into a predeterminedpattern by laminating a copper foil, for example on the second surfaceof the module base 133. A nickel layer having a thickness of 0.5 to 3 μmmay be provided, by plating, in a portion of the copper foil exposed tothe outside. On the nickel film, a gold layer having a thickness of 0.01to 0.3 μm may be further provided by plating.

Each contact terminal 135 is used for contacting an external contactmachine, such as an automatic teller machine. The contact terminals 135are connected to an element or the like incorporated in the IC chip 134,not shown.

The IC chip 134 and the connecting coil 131 are connected via a wire,not shown. The IC chip 134, the connecting coil 131, and the wireconfigure a closed circuit.

A plurality of contact terminals may be formed using a lead frame havinga thickness of 50 to 200 μm on the second surface of the module base133, and the connecting coil may be formed using a copper wire on thefirst surface of the module base 133.

The resin seal 136 can be formed of a known epoxy resin, for example.With the resin seal 136 being provided, the IC chip 134 can be protectedor a wire disconnection can be prevented.

An operation of the dual IC card 101 configured in this way will now bedescribed. FIG. 18 is an equivalent circuit diagram illustrating aprinciple of the dual IC card 101.

A high frequency magnetic field is induced in a reception/transmissioncoil D12 by a high frequency signal, not shown, generated by areception/transmission circuit D11 of a reader/writer (contactlessexternal machine) D10. The high frequency magnetic field is radiated asmagnetic energy.

At this time, when the dual IC card 101 is positioned within the highfrequency magnetic field, the high frequency magnetic field causes acurrent to flow through a parallel resonant circuit configured by theantenna 113 and the capacitive element 114 of the dual IC card 101.

A signal received by a resonant circuit formed of the main coil 119 andthe capacitive element 114 is transmitted to the coupling coil 118.Afterwards, the signal is transmitted to the IC chip 134 byelectromagnetic coupling between the coupling coil 118 and theconnecting coil 131.

Although not shown, if the dual IC card 101 receives power supply fromand communicate with an external contact machine such as an automaticteller machine, a terminal provided to the automatic teller machine isbrought into contact with the contact terminals 135 of the dual IC card101. Then power supply is received from and communication is performedwith a control unit of the automatic teller machine and the IC chip 134.

As described above, according to the dual IC card 101 related to thethird embodiment, the coupling coil 118 has the first coil segment 151provided to the first surface 112 a of the substrate 112 and the secondcoil segment 152 provided to the second surface 112 b thereof. Since thecoupling coil 118 is provided not only to the first surface 112 a of thesubstrate 112 but also to the second surface 112 b thereof, the degreeof freedom in arranging the coupling coil 118 in the card body 110 canbe increased.

Since both of the surfaces 112 a and 112 b of the substrate 112 areequipped with the coil segments 151 and 152, respectively, the degree offreedom can be increased in impedance matching adjustment ofelectromagnetic coupling between the connecting coil 131 of the ICmodule 130 and the coupling coil 118 of the card body 110. Thus, theimpedance characteristics different between IC chips 134 are morereliably coped with, and performances, such as power supply, areoptimized for more types of IC chips.

The second coil segment 152 is formed by being looped around the IC chip134 only once.

Accordingly, if the element wire 151 b of the first coil segment 151 andthe element wire 152 a of the second coil segment 152 overlap with eachother in the thickness direction D, the coil segments 151 and 152overlap with each other only by one round. Accordingly, increase andvariation in the capacitor's capacitance of the antenna 113 can beminimized.

The third embodiment of the present invention has so far been describedabove in detail with reference to the drawings. However, the specificconfiguration is not limited to this embodiment, but encompassesmodifications, combinations, or the like of the configurations, whichare made within the scope not departing from the spirit of the presentinvention.

For example, as shown in FIG. 19, in third embodiment, the width of theelement wire 152 a of the second coil segment 152 may be larger than thewidth of the element wire 151 b of the first coil segment 151 inportions of the overlap in the thickness direction D between the elementwire 151 b and the element wire 152 a. In this example, the width of theelement wire 152 a of the second coil segment 152 is larger than thewidth of the element wire 151 b of the first coil segment 151 by alength L1 of 0.5 mm in portions of the overlap in the thicknessdirection D between the element wire 151 b and the element wire 152 a.

The positional displacement caused by the etching of the resist-coatingmethod based on gravure printing mentioned above is approximately 0.5mm. For example, in forming the element wire 152 a, the element wire 152a may be displaced in the orthogonal direction F relative to the elementwire 151 b and formed at a position P. In the case where the elementwire 152 a is formed at a designed position or in the case where theelement wire 152 a is formed at the position P displaced from thedesigned position, a length L2 in the orthogonal direction F remainsunchanged in portions where the element wires 151 b and 152 a face eachother.

With this configuration, the capacitor's capacitance can be suppressedfrom being varied between the element wires 151 b and 152 a, dependingon whether there is positional displacement of the element wire 152 a tothereby improve communication characteristics of the dual IC card 101.

The width of the element wire 151 b may be larger than that of theelement wire 152 a in the present modification.

As shown in FIG. 20, the first and second coil segments 151 and 152 mayhave portions where the segments do not overlap with each other whenviewed in the thickness direction D. With this configuration, generationof capacitor's capacitance by the element wires 151 b and 152 a can beminimized.

In the third embodiment, the second coil segment 152 is formed by beinglooped around the IC module 130 only once. This is applied to the caseof using an IC chip where communication characteristics are influencedby the variations in capacitor's capacitance formed between the firstand second coil segments 151 and 152. Accordingly, the number of timesby which the second coil segment 152 is looped around the IC module 130is not limited to once, but may be two or more times depending onperformance of the IC chip to be used.

In the case of using a configuration where the capacitive element 114can be adjusted after forming the antenna, variations in the capacitor'scapacitance formed between the first and second coil divided bodies 151and 152 can be cancelled. Accordingly, regardless of the characteristicsof IC chips, the number of times by which the second coil segment 152looped around the IC module 130 can be optionally determined, and anoptimal impedance matching design can be applied.

The configuration where the capacitive element 114 can be adjusted afterforming the antenna increases cost compared to the configuration wherethe capacitive element 114 cannot be adjusted after forming the antenna.Accordingly, to reduce cost and minimize variations in communicationcharacteristics, the number of times by which the second coil segment152 is looped around the IC module 130 is preferably not more than twotimes in the configuration where the capacitive element 114 cannot beadjusted after forming the antenna.

The element wire 151 b arranged innermost of the first coil segment 151and the element wire 152 a of the second coil segment 152 overlap witheach other around the IC chip 134 by one round when viewed in thethickness direction D. However, these element wires 151 b and 152 a onlyneed to overlap with each other at least partially when looped aroundthe IC chip 134.

In the third embodiment, the main coil 119 and the connecting coil 131are looped three times around the recess 111, while the first coilsegment 151 is looped five times around the recess 111. However, thenumbers of times by which these coils 118 and 119, and the first coilsegment 151 are looped are not limited to the numbers in theabove-described embodiment. The coils 118 and 119, and the first coilsegment 151 only need to be looped one or more times.

The number of the contact terminals 135 possessed by the contactterminal portion does not necessarily have to be two or more but may beone.

In the third embodiment, the width of the element wire 152 a of thesecond coil segment 152 is larger than the width of the element wire 151b of the first coil segment 151 by 0.5 mm in the portions where theelement wire 151 b and the element wire 152 a overlap with each other inthe thickness direction D. However, the width of the element wire 152 amay be configured to be larger than the width of the element wire 151 bby not less than 0.5 mm but not more than 1 mm. Positional displacementin forming the antenna by etching is approximately 0.5 mm as describedabove. Accordingly, as long as the displacement is within this range,the overlap between the element wires 151 b and 152 a can be madeconstant. Depending on designs, the width of the element wire 151 b maybe made larger than the width of the element wire 152 a.

Example

In an example of the dual IC card 101 shown in FIG. 16, the dual IC card101 was fabricated under the conditions described below.

The substrate 112 was formed of PET with a thickness of 38 μm. The firstsurface 112 a of the substrate 112 was laminated with an aluminum foilhaving a thickness of 30 μm, followed by the etching mentioned above tothereby form the antenna 113 and the capacitive element 114. The secondsurface 112 b was laminated with an aluminum foil having a thickness of20 μm, followed by the etching mentioned above to thereby form theconnecting wiring 121. The width of the element wire 151 b of the firstcoil segment 151 was 0.4 mm, while the width of the element wire 152 aof the second coil segment 152 was 0.9 mm.

Preferable embodiments of the present invention have so far beendescribed. However, these embodiments are only exemplifications of thepresent invention and should be construed as being limitative.Additions, omissions, replacements, and other changes can be madewithout departing from the scope of the present invention. Accordingly,the present invention should not be regarded as being limitative by thedescription provided above, but is limited by the appended claims.

REFERENCE SIGNS LIST

-   -   1, 1A, 1B, 1C, 1D, 1E, 101: dual IC card; 2, 110: card body; 2        a: first long side portion; 2 b: second long side portion; 2 c:        first short side portion; 2 d: second short side portion; 2 e:        front surface; 2 f: back surface; 3: IC module; 4: antenna; 4A:        coupling coil portion; 4B: main coil portion; 5: first embossed        area; 5 a: boundary; 6: second embossed area; 21: IC module        accommodating portion (recess); 22: first hole portion; 23:        second hole portion; 22 a: first side surface portion; 22 b:        second side surface portion (linear portion); 31: connecting        terminal portion (contact terminal portion); 32: module        substrate; 33: IC chip; 34: connecting coil; 41: sheet        substrate; 42: capacitive element; 51, 52, 53B, 59A, 59B, 59C,        B3 a: resistance-increasing portion (first bent pattern); 53,        53C, 54, 58: wiring portion; 53A, 54A, 53C, 54C, A1 a, A1 c, A1        d, A2 a, A2 c, A2 d, A3 a, A3 c, A3 d, A4 a, A4 c, A4 d, A5 a,        A5 c, A5 d, B1 a, B1 c, B2 a: thin line portion; 54B:        resistance-increasing portion (second bent pattern); 55: end        wiring; 56: meandering wiring (second bent pattern); 57: end        wiring; 59 a, 59 b: spiral wiring; 111: recess; 111 a: opening;        112: substrate; 112 a: first surface; 112 b: second surface;        113: antenna; 118: coupling coil; 119: main coil; 130: IC        module; 131: connecting coil; 134: IC chip; 135: contact        terminal (contact terminal portion); 151: first coil segment;        151 a, 151 b, 152 a: element wire; 152: second coil segment; A1,        A2, A3, A4, A5, B1, B2, B3, B11, B12, B13: coil wiring; A1 b, A2        b, A3 b, A4 b, A5 b, B1 b, B2 b, B3 b, B3 c, B3 d: thick line        portion; Atc, Atd: line width transition portion; B1 d, B2 c, B2        d: lateral wiring portion; B3′: equivalent coil wiring; Lb:        extension line; Pb, Pa, Pd, Pc: corner portion; O: straight        line; S1: opening area increase; S2: opening area decrease; D:        thickness direction; D10: reader/writer

What is claimed is:
 1. A dual IC card comprising: an IC module includinga contact terminal portion contacting an external machine, a connectingcoil configuring a contactless terminal portion by electromagneticcoupling, and an IC chip having a contact communication function and acontactless communication function; an antenna including a coupling coilstructured to electromagnetically couple with the connecting coil of theIC module, and a main coil connected to the coupling coil to performcontactless communication with an external contactless machine; and aplate-like card body in which a recess is formed for accommodation ofthe IC module, wherein: the card body has a substrate; and the couplingcoil includes a first coil segment provided on a first surface of thesubstrate, which serves as an opening side of the recess of thesubstrate, and a second coil segment provided on a second surface of thesubstrate.
 2. The composite IC card according to claim 1, wherein: theantenna further comprises a capacitive element; the capacitive elementhas a first electrode plate provided on the first surface of thesubstrate, and a second electrode plate provided on the second surfaceof the substrate; the first electrode plate provided on the firstsurface of the substrate is connected to the main coil, and the secondelectrode plate provided on the second surface of the substrate isconnected to an end of the second coil segment.
 3. The dual IC card ofclaim 1, wherein: the first coil segment and the second coil segment atleast partially overlap with each other when viewed in a thicknessdirection of the substrate; and the first coil segment and the secondcoil segment have respective element wires with different line widths inportions where the first coil segment and the second coil segmentoverlap with each other in the thickness direction.
 4. The dual IC cardof claim 3, wherein the difference in line width of the respectiveelement wires of the first coil segment and the second coil segment isnot less than 0.5 mm in portions where the first coil segment and thesecond coil segment overlap with each other in the thickness directionof the substrate.
 5. The dual IC card of claim 3, wherein a width of anelement wire of the second coil segment is larger than a width of anelement wire of the first coil segment.
 6. The dual IC card of claim 1,wherein the first and second coil segments have portions where thesegments do not overlap with each other when viewed in a thicknessdirection of the substrate.